The County-Designated Highways in Michigan comprise a system of primary county roads across the state. Unlike the Michigan State Trunkline Highway System, there is a zone arrangement to the numbering of these highways. The CDH system was created in 1970 in response to the business concerns of a woman from Saugatuck. Her one-woman crusade in the 1960s started after the highway in front of her motel was turned over to local control as a county road and removed from state highway maps when the nearby freeway opened. After nearly a decade of efforts, the two test highways were designated, one each in the Lower and Upper peninsulas of the state and included on the 1970 state highway map. The CDH system was created and expanded in scope c. October 5, 1970, after it was approved by the County Road Association of Michigan and the State Highway Commission.
The system uses eight lettered zones which are divided by major state highways. Each county road in the system is designated with the zone letter followed by a number. Six of the zones, A–F, are in the Lower Peninsula while the Upper Peninsula is divided into the remaining two, G and H. There have been a total of 71 different highways designated in seven of the zones; as of 2010 no E highways have been named. Participation by the county road commissions is optional, and not all counties use the system. One additional highway, H-16, has appeared on state maps since the 1980s although it is not a part of the system.
When the Interstate 196 (I-196) freeway was built in the Saugatuck area in the 1960s, US Highway 31 (US 31) was shifted to the new freeway. The former route along Blue Star Highway was returned to county jurisdiction, which removed the various state highway markings from the roadway and displaced Blue Star Highway from the state highway maps of the time. At the time, Mr. and Mrs. Howard and "Gene" Temple owned a motel along the roadway in Saugatuck, and they were dismayed over the number of cancelled reservations they were receiving because guests could not find their business. Mrs. Temple approached the Village of Saugatuck, the local chamber of commerce to get better highway markings for the area. She even contacted state legislators and members of the State Highway Commission. No changes were made, even though businesses along Blue Star Highway were suffering from a lack of traffic.
H-58 west of Grand Marais
Mrs. Temple contacted officials at the Allegan County Road Commission and the County Road Association of Michigan in August 1968. State Senator Gary Byker of Hudsonville was also contacted, and he convened meetings with representatives on the state, county and local levels in search of a solution. These meetings resulted in a test program for the 1970 state highway map that marked Blue Star Highway as A-2; the Allegan County Road Commission spend $2000 to erect about 50 markers along the road in their county. A second road in the Upper Peninsula was designated B-1 between Engadine and Rudyard in Mackinac and Chippewa counties. Both county roads contained the caption "Experimental Program for Identifying Key County Roads". The markers used were the blue and yellow pentagon shields developed by the National Association of County Engineers. Mrs. Temple earned the honor as the first woman in "Michigan to obtain a highway designation from the State Highway Commission".
F-26 in Ogemaw County
The program was implemented by October 5, 1970, and expanded in scope. Instead of using designations beginning with an A for county roads in the Lower Peninsula and with a B for those in the Upper Peninsula, the system was divided into eight zones. The first of these revised assignments were shown on the 1971 state highway map; A-2 retained its number by B-1 was renumbered to H-40 in the Upper Peninsula. Earl Rogers, the engineer-director of the County Road Association of Michigan stated at the time that the county road commissions would gradually phase in signage over the coming years. Participation in the system was made optional, but all counties had agreed to the system.7 As of 2012, no counties in the E zone have assigned roads to the system, and many counties in the other zones have yet to participate.
As implemented in October 1970, the CDH system is divided into eight zones: six in the Lower Peninsula and two in the Upper Peninsula. This contrasts to the state highway system that makes no attempt to group designations by geography in the state. The boundaries for each zone are determined by major state trunkline highways on each peninsula. Each highway is given a designation composed of the zone letter followed by a two-digit number. Within the zone, numbers are assigned on a grid system: north–south highways use odd numbers and east–west highways have even numbers. Lower numbers are used to the south or west sides of the zones.
The Lower Peninsula is divided into six zones, A-F:
The A zone is bordered by I-96 on the north and US 127 on the east.
The B zone is bordered by I-96 on the south, US 10 on the north and US 127 on the east.
The C zone is bordered by US 10 on the south and both I-75 and US 127 on the east.[a]
The D zone is bordered by US 127 on the west and I-96 on the north.
The E zone is bordered by US 127 on the west, I-96 on the south and US 10 on the north. As of 2012, no highways have been designated in the E zone.
The F Zone is bordered by both I-75 and US 127 on the west and US 10 on the south.[a]
The Upper Peninsula is divided into the G and H zones. The dividing line between the two zones is US 41, between Lakes Michigan and Superior with zone G lying west of US 41 and zone H lying east of it.
A-2 is located in the southwestern part of the Lower Peninsula and runs along near the shoreline of Lake Michigan. It was originally part of US 31 before the I-196/US 31 freeway was built. It was the first county designated highway in the Lower Peninsula. The route's southern terminus is at M-63 in the community of Lake Michigan Beach and its northern terminus is at US 31 south of Holland. The highway remains a two-lane undivided highway for most of its length, with a few divided portions. The highway is about 50 miles long. It has long been referred to by local residents as the Blue Star Memorial Highway in honor of "Blue Star" veterans who served the United States military during World War II.
A-37 begins at M-222 in Allegan, running northerly to a terminus at I-196 in Hudsonville, by way of Monterey and Burnips. The route follows 30th Street through Allegan County, which becomes 24th Avenue in Ottawa County. The route then turns west on Byron Road south of Jamestown, and north on 32nd Avenue.
A-42 runs for 16.4 miles (26.4 km) in Allegan County. The western terminus of A-42 is at M-40 just north of Dunningville, having been extended westerly from A-37 in 1993. Its eastern terminus is at a junction of US 131 and M-179 near Bradley. A-42 begins at an intersection with M-40 north of Dunningville. It follows 128th Avenue eastward to 13th Street. A-42 follows 13th Street northward for 0.75 miles (1.21 km) to a junction with 129th Avenue. From there, it turns eastward again along 129th Avenue to the US 131/M-179 interchange.
The original segments of the highway were designated in 1982. A-42 originally continued from US 131 another 16.963 miles (27.299 km) to M-43 west of Hastings. This routing followed Metz, Bowen's Mill and Gun Lake roads.  This portion of A-42 was transferred to the state as M-179 on October 31, 1999 as a part of then-governor John Engler's Rationalization plan.
B-23 follows Russell Road from US 31 north of North Muskegon to B-86 northeast of the Montague/Whitehall area. The route runs through the village of Lakewood Club. The road also provides access to the Michigan's Adventure theme park.
B-35 runs from I-96 in Coopersville to M-82 near Fremont. It includes the former routing of the first designation of M-213 between Muskegon and Brunswick. M-213 was turned back to local control in 1960 and became B-35 in the 1970s. South of Ravenna, the route is co-signed with B-72.
B-72 makes its course in Kent, Ottawa and Muskegon Counties. It runs westward from the US 131/M-57 interchange on 14 Mile Road, south on Algoma Road for one mile, west on 13 Mile Road through Sparta, and going through Ottawa County, then Muskegon County on Ellis Road. It then turns north onto Ravenna Road. through Ravenna, then northwestward and westward on Price Heights, Sherman, and Evanston roads.
B-88 followed Baseline Road easterly from White Cloud, before turning north on Newcosta Avenue and east on 8 Mile Road to end at US 131 west of Stanwood. The 15.416-mile-long (24.810 km) B-88 designation was created in 1984, and it was retired in 1998 when it was supplanted with a re-routing of M-20 east of White Cloud.
C-58 runs easterly from Petoskey to an eastern terminus at exit 301 off I-75 just east of Wolverine in southwest Cheboygan County. The western terminus is uncertain. Signage on Michigan's county-designated highways is typically haphazard and there is no precise indication as to where the designation ends. However, the signage disappears west of the intersection with C-81 just east of Petoskey.
The highway is also known as Mitchell Road in Emmet County and as Wolverine Road in Cheboygan County, except in the village of Wolverine, where it is known as Main Street. Some maps also label it as Silver Lake Road west of Wolverine.
C-66 runs about 28 miles (45 km) across the northern tip of the Lower Peninsula. The roadway starts in the unincorporated community of Cross Village in Emmet County at an intersection with M-119 and C-77. It follows Levering Road through rural areas to an interchange with Interstate 75 (I-75) west of Cheboygan. The eastern terminus is at an intersection with US Highway 23 (US 23) and M-27 in downtown Cheboygan. The first roadways along what is now C-66 were in place by the early 20th century. Segments were paved by 1936, although some reverted to a gravel surface during World War II. The full roadway was paved by the mid-1950s, and the C-66 moniker was designated on the roadway in the early 1970s.
C-81 consists of two discontinuous segments. The southern segment extends from the junction of US 131 and M-75 in the community of Walloon Lake then extends to US 31 north of Petoskey. The northern segment follows Pleasant View Road going north in Emmet County, then turns east onto Gill Road, north onto Cecil Bay Road to Cecil Bay Corners, east onto Wilderness Park Drive, then east into Mackinaw City, ending one block north of the northern terminus of M-108.
F-01 runs northerly from County Road 612 west of Lewiston northerly to F-44 north of Vienna. The route runs along the Otsego/Montmorency county line, which is also the Michigan Meridian, for its entire length.
F-05 is located in Cheboygan County and follows Black River Road northward, northward and westward on Abby Road, northward on Gaynor Road, west on Page Road, and north and northwest to Butler Road, and Butler Road to US 23 on the eastern city limit of Cheboygan.
F-07 consisted of two segments, both in Ogemaw County. The southern segment followed Cook Road from F-18 (Greenwood Road) south of West Branch to just south of the city limits, then west on Flowage Lake Road, north on 1st Street, west on Griffin Road and north on 4th Street into downtown West Branch, ending at M-55. The northern segment followed Fairview Road from M-55 on the east side of West Branch northerly via the community of Damon to the Ogemaw/Oscoda County line. The highway is no longer designated.
F-17 followed Henderson Lake Road west of Prescott from the Ogemaw/Arenac county line northerly to F-26, northerly along the north-south portion of Greenwood Road (co-designated with F-26), northerly again along Shady Shores Road to F-28, westerly along Rose City Road (co-designated with F-28) to Lupton, northerly along Lupton Road through Lupton, easterly along Heath Road to South Branch, and then northwesterly along Mack Lake Trail to the Ogemaw/Oscoda county line. The highway is no longer designated.
F-18 follows Greenwood Road easterly from F-97 south of St. Helen through Skidway Lake and Prescott to the Iosco/Ogemaw county line. It then follows McLean Road southerly along this line to end at the juncture of the Iosco, Ogemaw and Arenac county lines. Official MDOT maps show the route ending at the Ogemaw/Roscommon county line, although the F-18 designation is signed along Greenwood Road in Ogemaw County; earlier maps from MDOT did not show the McLean road portion. The portion within the village of Prescott is part of the former M-70 designation.
F-19 followed the north-south portion of Sage Lake Road from south of Prescott northerly to the Sage Lake area, ending at a junction with F-26 (Town Hall Road at Sage Lake Road, which turns from north-south to east-west at this junction). The highway is still partially signed.
F-20 followed Mills Road on the north side of Prescott, then continued along Mills Road (which changes to Prescott Road within Iosco County) to M-65 through the community of Whittemore, before going east on Whittemore Road, north on Sand Lake Road and east on Townline Road to end at US 23 south of Tawas City. The Iosco county portion was removed around 1985.
F-21 begins at M-32 south of Hillman and ends at US 23 south of Rogers City. This route is also known as County Road 451 in Presque Isle County, and it overlaps with Business Spur M-32 within the village of Hillman. The southernmost half-mile of the route was formerly part of M-32 before that route was realigned to bypass Hillman.
A second F-21 designation followed East County Line Road along the Ogemaw/Iosco county line from F-24 northerly, crossing over into Iosco County via Flint and Long Lake Roads to end at F-28 (junction of Long Lake, South Branch and Mercury Roads) in the community of Long Lake. This second F-21 is no longer designated.
F-26 followed Sage Lake Road from F-7 north of West Branch to the Sage Lake area. At the junction of Town Hall Road (where Sage Lake Roads turns from east-west to north-south), F-26 continued easterly via Town Hall Road to the county line. Before 1985, F-26 continued easterly through Hale via Esmond Road, then headed easterly and southeasterly via Vaughn, Indian Lake, Beck and Plank Roads through the Sand Lake area to end at M-55 west of Tawas City. The highway is no longer designated.
F-28 runs from F-97 in St. Helen, along Rose City Road through Rose City and Lupton to the Iosco/Ogemaw County line. As with F-18, only the Roscommon County portion is shown on official MDOT maps, although F-28 is signed throughout all of Ogemaw County. The route previously continued easterly along Mercury Road (the Iosco County portion of Rose City Road), jogged northerly on South Branch Road, then easterly via Kokosing Road to end at M-65 north of Hale.
F-32 begins at Business Loop I-75 in Grayling. The route runs along North Downriver Road north of Grayling, which becomes Miller Road (also County Route 608) in Oscoda County. West of Fairview, it is concurrently signed with M-33 and M-72 southerly to Mio. From there, it runs easterly along McKinley, Old State, Au Sable and Aspen Alley Roads through the community of McKinley, ending at M-65/M-72 south of Curran.
Although it has been a county road since 1960, F-41 was a state highway in 1919 when the state trunkline highway system was formed. It was a segment of the original M-10 that was replaced by US 23 in 1926. Later changes to US 23 shifted that road closer to Lake Huron, and the Michigan State Highway Department (MSHD) created two different routings for M-171 out of the former US 23 routings in the area. The second of these highways has been designated F-41 since 1970.
F-97 is located in Gladwin, Roscommon, Crawford, and Otsego counties. It begins at a junction with M-18 about seven miles north of Gladwin. It runs mostly north-south, crossing I-75 in Roscommon County. Access is through Exit 227 with M-55 about a mile to the west. The route then cuts to the east for about four miles before continuing north through St. Helen. In Crawford County, just north of the Roscommon County boundary, the route runs concurrently with M-18 for about four miles in South Branch Township. Where M-18 has its northern terminus at the junction with M-72, F-97 continues north through Lovells along a winding path that is roughly parallel with the North Branch Au Sable River. The northern terminus is at M-32 south of Johannesburg, although MDOT maps show it ending at F-38.
G-30 ran from Randville to Hyde via Felch. Before 1960, this route was part of M-69 The transfer to county control was part of a program to reduce the total state highway mileage in the state. At varioUS points, the road commissions in Dickinson, Menominee and Delta counties tried to give the roadway back to the state for maintenance. Menominee County made the request in 1974 and 1982, both times rejected because the road did not carry enough traffic to be a state highway. The road was a maintenance issue for the counties because of its relative isolation and high truck traffic carrying pulpwood to the paper mill in Escanaba and potatoes from farms near Felch. The roadway was in a relative state of disrepair in 1982, and the counties wanted the state to fix it. Menominee County estimated that it would cost $500,000 (equivalent to $1.22 million in 2014) for their 18-mile (29 km) stretch, while Dickinson estimated that it would cost $1 million for their 27 miles (43 km). This county road designation lasted until 1993. That year, the changes made in 1960 were reversed and M-69 was re-extended along M-95 and back to the Bark River area.
H-13 is a county-designated highway in the US state of Michigan that runs north–south for approximately 36.2 miles (58.3 km) between Nahma Junction in Delta County and the Munising area in Alger County. The highway is also signed as Federal Forest Highway 13 (FFH-13), a Federal Forest Highway between Nahma Junction and Wetmore. The roadway runs through rural national forest lands providing access to several campgrounds and parks. The area contains several lakes as well. The Forest Highway System dates back to the 1920s, and an earthen roadway was present along the route of FFH-13 by the 1930s. It was paved by the late 1940s and added to the county-designated highway system in the 1970s. A section of H-13 in Alger County originally continued north to Miners Castle, but the roadway designation was truncated in the first decade of the 21st century.
Federal Forest Highway 16 (FFH 16) is a forest highway in the western Upper Peninsula of the US state of Michigan. This road runs through the Ottawa National Forest in Iron, Houghton and Ontonagon counties. The Michigan Department of Transportation (MDOT) has erroneously marked it as H-16 on their official state map. FFH 16 is designated by the US Forest Service (USFS) with maintenance shared by the county road commissions (ICRC, HCRC, OCRC, respectively). Although the MDOT maps would suggest that it is a part of the CDH system, it is not. The three counties in question do not participate in the system, and the roadway falls in the middle of the G zone for numbering purposes.
From 1929 until 1960, the road was part of the state highway system as M-135. The northern end of the highway always contained a section that ran concurrently with M-98, another state highway in the area. For a period in the 1950s, M-135 had a different northern terminus separate from M-98's endpoint. A few years before both highways were removed from the highway system, M-135 was moved to use M-98's terminus with M-28. Since the 1970s, M-135 has been a part of the county-designated highway system and assigned the number H-33, a moniker it has borne since.
H-40 was originally part of M-48 from Rudyard to Garnet, where M-48 turned north. The rest of H-40 to about 4 miles west of Engadine was originally part of US 2. When the county highway system was instigated in Michigan, H-40 was originally known as B-1. The route's western terminus is at M-117 in Engadine, and its eastern terminus at M-48 in Rudyard.
Two H-44 designations exist. The eastern section from Helmer at H-33 to Germfask was originally part of M-98 in the 1930s. The western section in Alger County begins at an intersection with US 41 at Kiva, continues through an intersection with H-01 at Traunik, and then ends at an intersection with M-67 and Storm Road just south of Limestone.
A roadway was present along parts of today's H-58 by the late 1920; initially this county road was gravel or earth roadway between Munising and Kingston Corners and used other roads to connect to Grand Marais. In the 1930s, the road was built to connect to Deer Park and to fill in the gap between Kingston Corners and Grand Marais. The southwestern segment between Munising and Van Meer was used as a section of M-94 from 1929 until it was transferred back to county control in the early 1960s. The H-58 designation was created after the county-designated highway system itself was formed in 1970. Initially only the section of H-58 Grand Marais to Deer Park was given the number ; the remainder was added in 1972. The last sections to be paved in the 20th century were completed in 1974. The National Park Service was required to build their own access road for the Pictured Rocks National Lakeshore in the initial legislation that created the park. This requirement was rescinded by the United States Congress in 1998, and the park service was authorized to fund improvements to H-58 instead. Paving projects were completed between 2006 and 2010 so that the entire length of H-58 in Alger County is now paved; the section in Luce County is still a gravel road.
H-63 parallels the Interstate 75 (I-75) corridor between St. Ignace and Sault Ste. Marie. The road is called Mackinac Trail after the Upper Peninsula branch of an Indian trail used before European settlers reached the area. Originally, the roadway was built as a section of US Highway 2 (US 2) before being added to the CDH system in the 1970s.
H-63 serves as a two-lane alternative to the I-75 freeway across the eastern end of the Upper Peninsula. Between the northern side of St. Ignace, the roadway has connections to two state highways before running concurrently with M-48 near Rudyard. H-63 ends on the south side of Sault Ste. Marie.