The highway spans a length of 294 miles (473 km) and is generally two-lane local road with the exception of urban multilane arterials within some cities.

The highway turns north after a three-mile (4.8 km) northeast stretch out of the city and passes through Eastman and Mount Sterling.

WIS 27 turns north off the concurrency in Westby and crosses into Monroe County near Newry.

[4] WIS 27 junctions with US 12 east on the south side of Black River Falls.

[7] The entire stretch of WIS 27 is due north–south and passes through only one city, Ladysmith, midway through the county.

[11] When first added as part of the original Wisconsin state trunkline in 1918, WIS 27's northern terminus was at Sparta.

[13][14] When US 61 was added in the late 1920s, WIS 27 was re-routed to Fennimore from Viroqua until 1932—when it was restored to its original routing to Prairie du Chien.