|Lower Peninsula of Michigan|
The Flint/Tri-Cities Region or Saginaw Valley is a region in the Lower Peninsula of the U.S. state of Michigan. The region is composed of the area surrounding Flint, Michigan, the Tri Cities, the Saginaw Bay and Saginaw River. In general terms, this area makes up the greater region of Mid-Michigan.
The Flint and Tri-Cities area, as well as most of Michigan is dependent on manufacturing. Automobile manufacturing is most prevalent in Saginaw and Flint, whereas Midland is the headquarters of the Dow Chemical Company, the world's second largest chemical producer. Rural areas grow crops such as sugar beets, navy beans, corn, fruits, and fish from the Saginaw Bay and Lake Huron.
Several large corporations have operations in the Tri-Cities. The Michigan Sugar Company, which is a cooperative owned by 1,250 farmers, operates factories in Bay City, Caro, Croswell, and Sebewaing. General Motors operates the Flint Truck Assembly factory in Flint and Powertrain plants in Flint, Bay City, and Saginaw. The Dow Chemical Company's world headquarters is based in Midland, as is the world headquarters for Dow Corning. The world headquarters of Nexteer Automotive is located in Saginaw. S.C. Johnson and Son has a manufacturing facility in Bay City making Ziploc products.
International Trade Corridor 
The I-69 International Trade Corridor is a strategic commercial gateway between the Midwestern United States and Ontario, Canada, with multi-modal transportation infrastructure that offers a wide range of distribution options.The I-69 International Trade Corridor Next Michigan Development Corporation (NMDC) offers economic incentives to growing businesses, both existing and new, that utilize two or more forms of transportation to move their products and are located within the territory of the NMDC. The I-69 International Trade Corridor Next Michigan Development Corporation is the largest in the state of Michigan with 35 municipal partners. 
Counties included 
The Greater Tri Cities 
The Thumb 
Main article: The Thumb
- Huron County, Michigan
- Tuscola County, Michigan
- Sanilac County, Michigan
- Lapeer County, Michigan
- St. Clair County, Michigan
Outlying Areas 
- Oakland County, Michigan (parts)
Addison, Brandon, Clarkston, Groveland, Highland, Holly, Oxford, Rose, Springfield, and Milford.
Geographic features 
The area has many lakes and rivers.
- Cass River has many branches, one of which flows into the Shiawassee River in the Shiawassee National Wildlife Refuge at less than a mile from where the Shiawassee merges with the Tittabawassee River to form the Saginaw River
- The Saginaw Bay forms a low basin known as the Saginaw Valley, which covers most of the region.
- Lake Huron rests in the far eastern portion of the area, known as the thumb
- St. Clair River, connects Lake Huron to Lake St. Clair, and is the farthest east border in Michigan. It forms a low impression in eastern St. Clair County, and has a delta at its mouth (North America's largest freshwater delta), which includes Harsens Island and Walpole Island, Ontario. Ferries cross the river at Algonac and Marine City, these being international border crossings.
- Flint River Flows through the central and southern portion of Lapeer County, west into Genesee County, and then merges into the Saginaw River.
Airlines and airports 
Scheduled airline service is available from MBS International Airport near Midland, Michigan and Flint Bishop International Airport. The only international airport in the thumb area is St. Clair County International Airport about 6 miles outside Port Huron.
Interstate highways 
- I-69 cuts through the southern area of the region. It starts at the Blue Water Bridge in Port Huron, and runs through Flint.
- I-75 connects this region together. It runs through Bay City, Saginaw, and intersects with I-69 in Flint. I-75 is very busy, bringing commuters north from Metro Detroit to the Mackinac Bridge and into the Upper Peninsula of Michigan.
U.S. Highways 
- US 10 bypasses Midland and terminates at I-75 in Bay City, merging into M-25. Viewed from an east-west orientation, it provides a mainly westerly road across Northern Michigan from Bay City off I-75 toward Ludington.
- US 23 comes out of Ohio merges with I-75 south of Flint, and then breaks away at Standish. It then proceeds north, along the Lake Huron shoreline to the Mackinaw City.
Michigan Highways 
- M-13 is a 72.22-mile (116.23 km) north-south highway that cuts through the bay region of the U.S. state of Michigan. The southern terminus is at I-69 south of the town of Lennon with its northern terminus located south of Standish. It is a shorter alternative route, instead of I-75, from Bay City to US 23 in Standish.
- M-25 is a highway of an arc-like shape closely following the outline of the Thumb along the Lake Huron/Saginaw Bay shoreline between Port Huron and Bay City. It is generally a scenic drive.
- M-46 is a cross peninsular road, running across the mitten and the thumb—from Port Sanilac on the Lake Huron shore; through Saginaw near Saginaw Bay; and then on to Muskegon on the Lake Michigan shore. This east-west surface route nearly bisects the Lower Peninsula of Michigan latitudinally.
- M-53 (Van Dyke Road) is a gateway route to The Thumb of Michigan, carrying vacationers to the resorts and cottages on Saginaw Bay and Lake Huron in the vicinity of Caseville and Port Austin. It goes up the middle of the Thumb, and directly connects in Macomb County, Michigan to the M-53 expressway. It is an important route for agricultural and manufactured goods.
- M-54 The Dort Highway, A main road leading into Flint replaced by I-475
- Main article: Michigan Services
Local freight carriers are the Grand Trunk Western Railroad, CSX Transport, Canadian National, Huron and Eastern Railway, Lake State Railway, Saginaw Bay Southern Railway, and Great Lakes Central Railroad.
- Daily editions of the Detroit Free Press and The Detroit News are available throughout the area.
- Editions of the Bay City Times, Midland Daily News and Saginaw News are available in the greater Tri-Cities area. The Times and the Saginaw News published three times a week, while the Midland Daily News publishes daily. The Great Lakes Bay Edition, a joint publication between the Saginaw News and the Bay City Times, focuses on those two cities, as well as Midland, and publishes once a week.
- The Flint Journal is available in the Flint and Lapeer areas, as well as north Oakland county —it is published four times a week.
- The Huron Daily Tribune serves Huron County; it is published daily.
- The Port Huron Times Herald serves the lower Thumb communities; it is published daily.
The Flint/Tri-Cities area lies within four radio media markets.
Broadcast television 
Television in Tri-Cities and Flint is mostly produced from the Flint/Tri-Cities Television Market. Far eastern areas such as Lapeer County, St. Clair County and Sanilac County lie in the Detroit Television Market. Areas like Genesee County can view programing from the Detroit and Flint/Saginaw media markets. The Canadian Broadcast Corporation is available via antenna and carried by most cable providers in Southeast Michigan. Broadcasts in this region can be seen in English, Arabic, French, and Spanish, the four most commonly spoken languages here, besides American Sign Language.
Availability of stations depend on reception of aerial signals, as well as availability on cable and satellite in a particular area.
Principal cities 
Flint's population is 102,434; it is the seventh largest city in Michigan. The combined population of the Greater Tri-Cities (Saginaw, Midland, and Bay City) is 398,482. Genesee, St. Clair and Lapeer counties are located in Detroit–Ann Arbor–Flint Combined Statistical Area.
See also 
- Michigan Sugar Company
- http://i-69internationaltradecorridor.com/nmdc/ Next Michigan Development Corporation
- http://i-69internationaltradecorridor.com/about/ International Trade Corridor
- MBS International Airport
- Flint Bishop International Airport
- Bessert, Christopher J. "US-10". MichiganHighways.org.
- M-25 end point photos.
- M-46 Endpoint Photos.
- Bay City Times
- Saginaw News
- Flint Journal
- Clarke Historical Library, Central Michigan University, Bibliography on Michigan (arranged by counties and regions)
- Michigan Department of Natural Resources website, harbors, hunting, resources and more.
- List of Museums, other attractions compiled by state government.
- "Historic Light Station Information and Photography: Michigan". United States Coast Guard Historian's Office.
- Map of Michigan Lighthouse in PDF format.
- Seeing the Light, Terry Pepper on lighthouses of the Western Great Lakes.