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 4 follows 170th Street from its beginning at US Highway 61 until after its intersection with Olinda Trail in May Township.

County Road 6 heads eastward as Stillwater Boulevard towards its eastern terminus.

8 begins at the county line and after a short distance as Frenchman Road, has a concurrency with US Highway 61.

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 13 begins at Highway 36 just west of Interstate 694 in Oakdale as Hadley Avenue North.

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).

13 continues through Woodbury with a major intersection at Valley Creek Road (Washington County 16) before entering Cottage Grove.

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 into Bayport as 5th Avenue before it ends at 3rd Street (MN 95).

County Road 15 begins at an interchange with Interstate 94 and Minnesota Highway 95 South.

County Road 18 goes east and has a partial interchange with Interstate 494, providing access to US Highways 10 and 61.

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 begins at the entrance to Lake Elmo Park Reserve and is named Keats Avenue.

County Road 21 then adopts the name St. Croix Trail for itself, which it remains until it ends at US Highway 10 in southern Denmark Township, just west of Prescott, Wisconsin.

County Road 22 begins in St. Paul Park at an intersection with Broadway Avenue.

The road briefly carries the name Summit Avenue before becoming 70th Street South after passing US Highways 61 and 10.

County 23 then continues onto Paris Avenue before turning onto Orleans Street in Stillwater.

County Road 24 serves the cities of Stillwater and Oak Park Heights, as well as Baytown Township.

County Road 24 is known as Osgood Avenue and has a major intersection at Minnesota 36 in Oak Park Heights, before entering Stillwater.

County Road 25 begins at the interchange between Interstate 94 and Minnesota 120 near the town of Landfall.

26 begins at Osgood Avenue (Washington County 24) just south of an intersection with Minnesota 36.

It was renumbered in 2013 to avoid confusion with Minnesota State Highway 36, which it intersects at its southern end.

County Road 29 is known as Hilton Trail for its entire route, and serves the towns of Pine Springs and Mahtomedi.

County Road 39 enters Cottage Grove, following Hadley Avenue to 80th Street South.

61 begins at an intersection with Manning Trail North (Washington County 15) as 120th Street.

66 has a stoplight at Curve Crest Boulevard just before ending at Orleans Street West.

71 goes all the way through Afton and ends at 70th Street South (Washington County 22) in northern Denmark Township.