Washington County uses the standard blue pentagon to sign County State-Aid Highways (CSAH) and the white square to sign County Roads (CR).
CR 1–CR 20 County Road 2
County Road 2 is a county route in Forest Lake, Minnesota. It follows Broadway Avenue in Forest Lake from a roundabout at US Highway 61 to Interstate 35 just north of the split between I-35W and I-35E. County Road 2 then continues westward to the edge of the county where it becomes Anoka County Road 18. County Road 2 used to continue north on US Highway 61 and then follow North Shore Trail until it ended at Scandia Trail (MN 97) in eastern Forest Lake.
County Road 3 County Road 3 is a county route that serves Scandia and May Township. County Road 3 begins at Square Lake Trail (County Road 7) and continues north to 170th Street North (Washington County 4) in northern May Township. County Road 3 continues at 170th Street North (Washington County 4) in northern May Township as Olinda Trail North into Scandia where it intersects both County Road 52 and Scandia Trail (MN 97). Olinda Trail continues out of the county as Chisago County 25 as it heads towards the Chisago Lakes area. County Road 3 was extended south from its former southern terminus at 170th Street North south to Square Lake Trail. This section of road was originally signed as County Road 55.
County Road 4
County Road 4 is a county route which connects Hugo on the western side of Washington County, to Marine on St. Croix on the eastern edge of the county. County Road 4 follows 170th Street from its beginning at US Highway 61 until after its intersection with Olinda Trail in May Township. County Road 4 turns onto Broadway Street in Marine on St. Croix and then terminates almost immediately at St. Croix Trail (MN 95).
County Road 4A
County Road 4A is a short county route in the city of Hugo in Washington County. County Road 4A is a continuation of County Road 4 west of its roundabout at US Highway 61. County Road 4A also follows 170th Street west to the edge of the county where it becomes Anoka County Road 140.
County Road 5 County Road 5 is a county route in Washington County that connects Stillwater and May Township. In Stillwater, County Road 5 is known as Stillwater Boulevard before continuing onto Olive Street and then turning onto Owens Street. County Road 5 continues through a busy intersection with County Road 12 as Owens Street. County Road 5 then becomes Stonebridge Trail as it approaches Dellwood Road (MN 96). County Road 5 continues past Minnesota Highway 96 before terminating at Otchipwe Avenue (Washington County 11).
County Road 6 County Road 6 is a county route in the cities of Lake Elmo and Oakdale in Washington County. County Road 6 begins at an intersection on the county line between Minnesota Highway 120 and Minnesota Highway 5. County Road 6 heads eastward as Stillwater Boulevard towards its eastern terminus. County Road 6 has a concurrency with County Road 13 along its short route. County Road 6 terminates at a roundabout with Jamaca Avenue and 34th Street (Washington County 14).
County Road 7 County Road 7 is a county route that serves the towns of Hugo, Grant, and Marine on St. Croix. County Road 7's western conterminous is at the county line, where it begins going east as 117th Street North before becoming 122nd St N. County Road 7 has a short concurrency with Manning Avenue (Washington County 15) before turning onto Square Lake Trail. 7 becomes Paul Avenue and then Nason Hill Road before reaching Marine on St. Croix, where it ends at St. Croix Trail (MN 95).
County Road 8 County Road 8 is a county route that serves the town of Hugo in northern Washington County. 8 begins at the county line and after a short distance as Frenchman Road, has a concurrency with US Highway 61. County Road 8 then turns on Egg Lake Road and changes street names many times before terminating at County Road 7 .
County Road 9 County Road 9 is a county route in Washington County that serves the city of Grant. County Road 9 begins at 75th Street (Washington County 12) in southern Grant. 9 continues north as Jamaca Avenue County Road 9 terminates at County Road 7 in southern Hugo.
County Road 10 County Road 10 is known as 10th Street North for all of its route. County Road 10 serves the cities of Oakdale and Lake Elmo. 10 begins at the county line and goes east. County Road 10 has an interchange with Interstate 694 and is Exit 57 from the interstate. 10 continues east and has major intersections at both Inwood Avenue (Washington County 13) and Manning Avenue (Washington County 15). County Road 10 ends at Stagecoach Trail (Washington County 21) in West Lakeland Township.
County Road 11 County Road 11 is a county route that serves Stillwater and May Township. County Road 11 begins at Minnesota Highway 96 just west of its terminus at Minnesota 95. County Road 11 is known as Boom Road before it goes around a sharp turn and changes names to Otchipwe Trail. County Road 11 ends at Square Lake Trail (Washington County 7) in May Township.
County Road 12 County Road 12 is a county route that serves Mahtomedi, Willernie, Grant, and Stillwater in Washington County. Originally, County Road 12 began as Stillwater Road in Mahtomedi after an intersection with Wildwood Road (MN 244). After Highway 244 was decommissioned, 12 was extended east to begin at State Highway 120 on the county line. 12 then continues through Grant as 75th Street, and has a major intersection with Manning Avenue (Washington County 15) on the border with Stillwater. County Road 12 then changes names again to Myrtle Street before terminating at County Road 5 (Owens Street).
County Road 13 County Road 13 is a county route in Washington County that serves Oakdale, Lake Elmo, Woodbury, and Cottage Grove. County Road 13 begins at Highway 36 just west of Interstate 694 in Oakdale as Hadley Avenue North. CSAH 13 soon becomes 50th Street North before turning onto Olson Lake Trail. The segments of County Road 13 that follow Hadley Avenue and 50th Street were, until 2019, signed as CSAH 35. 13 then becomes Ideal Avenue and has a major intersection with 34th Street (County Road 14, Old Highway 5). County Road 13 then has a short concurrency with County Road 6 (Stillwater Boulevard) before turning onto Inwood Avenue It has major intersections at 10th Street (Washington County 10) and Interstate 94 (Exit 250) during this stretch before becoming Radio Drive. 13 continues through Woodbury with a major intersection at Valley Creek Road (Washington County 16) before entering Cottage Grove. In Cottage Grove, County Road 13, now Hinton Avenue, terminates at 70th Street South (Washington County 22).
County Road 14 County Road 14 serves the cities of Oakdale, Lake Elmo, and Bayport. 14 begins its route at Century Avenue (MN 120), the western boundary of the county. County Road 14 continues east on the former route of Minnesota Highway 5 as 34th Street, where it has major intersections at Interstate 694 and Ideal Avenue (Washington County 13). County Road 14 then enters a roundabout at Jamaca Avenue and Stillwater Boulevard (Washington County 6). County Road 14 adopts the name Stillwater Boulevard and continues through downtown Lake Elmo, before turning onto Manning Ave, where it has a very brief concurrency with County Road 15. County Road 14 turns onto 40th Street North. 14 becomes Olinda Boulevard at its intersection with Oakgreen Avenue (Washington County 65). County Road 14 becomes Osgood Avenue for a short period before turning onto 47th Street County Road 14 has a concurrency with County Road 21 (Stagecoach Trail) before turning yet again onto 50th Street North. County Road 14 continues into Bayport as 5th Avenue before it ends at 3rd Street (MN 95).
County Road 15 County Road 15 is a county route that serves the cities of Lake Elmo, Oak Park Heights, and Scandia as well as May, Baytown, and West Lakeland Townships. County Road 15 begins at an interchange with Interstate 94 and Minnesota Highway 95 South. County Road 15 goes north as Manning Avenue, and has a major intersection at 10th Street North (Washington County 10). 15 has a very short concurrency with County Road 14 before turning onto Stillwater Boulevard. County Road 15 comes to an interchange with Minnesota Highway 36 and Washington County 5, where it turns and has an unsigned concurrency with Highway 36. County Road 15 then turns onto Manning Avenue and has major intersections at 75th Street North (Washington County 12) and Dellwood Road (MN 96). 15 continues onto Manning Trail, has a major intersection with Minnesota 97, and continues out of the county to the north. County Road 15 is the longest county road in Washington County at 26 miles in length.
County Road 16 County Road 16 is known as Valley Creek Road and serves Woodbury for its entire route. County Road 16 begins at the western county line at Washington County 25 and Ramsey County 72. 16 continues east and has an interchange with Interstate 494 (Exit 59). County Road 16 has major intersections with Radio Drive (Washington County 13) and Woodbury Drive (Washington County 19), before ending at MN 95 on the Woodbury/Afton border. The County Road 16 designation previously ended at County Road 19, but in 2020 it was extended to MN 95.
County Road 17 County Road 17 is a county route that serves the cities of Grant and Lake Elmo. County Road 17 begins at 75th Street (Washington County 12) in Grant and goes south through a major intersection with Minnesota Highway 36. County Road 17 then continues through downtown Lake Elmo, where it has a concurrency with Washington County 14 (Stillwater Boulevard, Old Highway 5). County Road 17 continues south along Lake Elmo Avenue until it ends at 10th Street (Washington County 10).
County Road 17B County Road 17B is a short county route in the southern portions of Lake Elmo. 17B runs from the intersection between Lake Elmo Avenue (Washington County 17/17B) and 10th Street (Washington County 10). County Road 17B ends at the border with Woodbury above Interstate 94, where there is no interchange.
County Road 18 County Road 18 is a county route that serves the cities of Newport, Woodbury, Afton, St. Mary's Point, Lake St. Croix Beach, Lakeland Shores, and Lakeland. County Road 18 begins at an interchange with Maxwell Avenue (County Road 38) and US Highways 10 and 61 in Newport as Bailey Road. County Road 18 goes east and has a partial interchange with Interstate 494, providing access to US Highways 10 and 61. 18 goes through Woodbury where it has major intersections with Radio Drive (Washington County 13), Woodbury Drive (Washington County 19), and Manning Avenue (MN 95) before becoming 40th Street South. County Road 18 becomes Afton Boulevard and then enters downtown Afton, where it has a short concurrency with Washington County 21 (St. Croix Trail). County Road 18 takes on the name of St. Croix Trail for the rest of its route through St. Mary's Point and Lake St. Croix Beach, goes around three roundabouts while serving the small towns of Lakeland and Lakeland Shores, and ends at the interchange between Interstate 94 and St. Croix Trail (MN 95 North, Washington County 18 South, Exit 258).
County Road 19