County routes in Genesee County, New York, are not posted on route markers. However, the number is given, along with house numbers, often on intersection blade signs. There is no apparent numbering pattern. County routes generally comprise one or more named roads, or portions thereof, strung together to form a single continuous unit. These usually extend for some distance, connecting primary highways in two or more towns. The majority of the county's roads are assigned to the towns. Nowhere does any county route wholly enter either a village or the city of Batavia. Routes 11 through 20 are listed below.
County Route 11 is a 3.37-mile (5.42 km) highway located within the town of Pembroke. CR 11 begins at the Erie County line as the continuation of CR 252 (Indian Falls Road) and follows Akron Road east to an intersection with NY 77 (Alleghany Road) near the hamlet of Indian Falls.
County Route 12 is an east–west highway that extends for 17.33 miles (27.89 km) through the towns of Alabama, Oakfield, and Elba. The route begins at the point where NY 77 crosses into Genesee County from Niagara County. From there, it overlaps NY 77 southeastward through the northwestern part of the town on Lewiston Road, passing to the south of the Iroquois National Wildlife Refuge and north of the Tonawanda Wildlife Management Area. The overlap between NY 77 and CR 12 ends at an intersection with NY 63 in the hamlet of Alabama, where NY 77 turns southward to join NY 63 while CR 12 continues eastward on Lewiston Road.
The route heads due east on Lewiston Road for roughly 4 miles (6 km) through the town of Alabama before arriving at a junction with Lockport Road. At this point, Lewiston Road forks off to the southeast toward the village of Oakfield while CR 12 follows Lockport Road east into the town of Oakfield and, farther east, the town of Elba. About 1 mile (2 km) north of the village of Elba, CR 12 intersects NY 98 (Quaker Hill Road). At this point, CR 12 changes names one final time, becoming North Byron Road. The route ends 2.5 miles (4.0 km) later at a junction with Barrville Road (CR 7), at which point North Byron Road becomes part of CR 7.
County Route 13 is a designation split into two segments by a roughly 2-mile (3 km) segment of NY 262 in the town of Byron. The western segment begins at the Batavia city line in the town of Batavia and ends at NY 262 west of the hamlet of Byron while the eastern segment is little more than an internal designation for a county-maintained segment of NY 262 between NY 237 in Byron and NY 19 just inside the Bergen village line.
The western segment of CR 13 runs in a north–south direction from the Batavia city line to the town of Byron. The roadway heads northeastward through the town of Batavia as Bank Street Road, the continuation of Batavia's Bank Street, to the Genesee County Airport, where it meets East Saile Drive (CR 46). Past the airport, CR 13 leaves the town of Batavia and proceeds northeasterly through the southeastern corner of the town of Elba to the town of Byron. CR 13 ends upon intersecting NY 262 (Byron–Elba Road), here state-maintained.
The eastern segment of CR 13 is the internal designation for a county-maintained segment of NY 262 between NY 237 in Byron and NY 19 just inside the Bergen village line. The entirety of this segment of CR 13 is known as Townline Road.
County Route 14 is an east–west route in the towns of Byron and Bergen. It begins at an intersection with NY 237 (Byron–Holley Road) just north of the hamlet of Pumpkin Hill and proceeds east–northeast as North Bergen Road into the town of Bergen and through the hamlet of North Bergen. Near the Monroe County line, CR 14 intersects West Sweden Road (CR 6), which briefly breaks CR 14. The route resumes just north of there as Reed Road, which runs along the Monroe County line for 0.79 miles (1.27 km) before entering Monroe County as CR 235.
County Route 15 is a north–south highway located mainly within the town of Bethany. CR 15 begins at the intersection of Silver and Chaddock Roads in the southwestern corner of the town and proceeds east as Linden Road, named for the hamlet it passes through. After 0.5 miles (0.8 km), CR 15 intersects Skates Hill Road (CR 15A), which links CR 15 to CR 1 in Wyoming County. Linden Road and CR 15 head generally northeasterly to the junction of Linden, Raymond (CR 49), and Bethany Center roads, where CR 19 turns northward to follow Bethany Center Road into the hamlet of Bethany Center. Here, CR 15 intersects US 20 (Broadway) before leaving the community. The route crosses into the town of Batavia just before ending at an intersection with NY 63.
County Route 15A is a short, 0.47-mile (0.76 km) spur of CR 15 in the town of Bethany. The highway, named Skates Hill Road, runs north–south from CR 15 (Linden Road) to the Wyoming County line, where the roadway becomes CR 1.
County Route 16 is an east–west route located in the towns of Oakfield and Elba. CR 16 begins at the Oakfield village line as North Pearl Street and heads north to an intersection with Maltby Road. Here, CR 16 turns east and assumes that name. The route remains on an east–west routing until it reaches the Elba village line, where the name and county route designation both end.
County Route 17 is the designation assigned to Parmelee Road and Oatka Trail in the town of Le Roy. Parmelee Road is a north–south loop road that begins and ends at junctions with NY 19 (Lake Road) while Oatka Trail is an east–west road that begins at Parmalee Road and follows Oatka Creek east to the Monroe County line, where the roadway becomes CR 245 (Oatka Creek Road). The two legs of Parmelee Road and Oatka Trail are a combined 4.40 miles (7.08 km) in length.
County Route 19 is a north–south highway located in the northwestern part of the town of Stafford and southern part of the town of Byron. CR 19 begins at an intersection with NY 33 and heads northward as Batavia–Stafford Townline Road. After intersecting College Drive (CR 48), the route turns to the northeast and becomes Byron Road. From here, CR 19 heads northeasterly, intersecting Prole Road Extension (CR 19B) and School Road (CR 19C) as it heads through Stafford. North of School Road, CR 19 follows a more northeasterly routing as it passes the Batavia Country Club and approaches the intersection of Byron and Walkers Corners Roads. Here, Walkers Corners Road switches designations from CR 42 to CR 19 while Byron Road becomes CR 19A. CR 19 heads east on Walkers Corners Road for roughly 1.5 miles (2.4 km) before ending at a junction with NY 237 in the hamlet of South Byron.
County Route 19A is a north–south highway in the towns of Byron and Bergen. It begins at the intersection of Byron and Walkers Corners Roads in Byron, where it connects to CR 19 and CR 42. CR 19A heads in a north-northeast direction through the town of Byron as Byron Road, intersecting NY 262 and NY 237 near the hamlet of Byron. Past NY 237, CR 19A becomes Warboys Road and heads in a more northeasterly direction as it travels into the town of Bergen. In Bergen, the route briefly overlaps with CR 6 on West Sweden Road before continuing eastward on Creamery Road to its end at a junction with NY 19 (North Lake Road).
County Route 19B is a north–south highway located in the towns of Bethany and Stafford. CR 19B begins at an intersection with NY 63 in the Bethany hamlet of Little Canada and heads north as Fargo Road into the town of Stafford. Roughly 3 miles (5 km) north of NY 63, CR 19B intersects NY 5 (East Main Street Road) and becomes Prole Road. The highway continues in a northerly direction to a junction with NY 33 (Clinton Street). At this point, CR 19B becomes Prole Road Extension and turns to follow a more northeasterly routing along the south side of the New York State Thruway (I-90). CR 19B ends at a junction with CR 19 not far to the northwest.
County Route 19C is a short spur off of CR 19 in the town of Stafford. Named School Road, it heads south from CR 19 for about 1,000 feet (305 m) before ending. At this point, School Road turns east and continues as a town highway.
County Route 20 is a 1.25-mile (2.01 km) highway located within the town of Pavilion. CR 20 begins at South Street Road (CR 3) and follows Walker Road east to the Livingston County line, where it becomes CR 23.