WIS 64 and WIS 107 run alongside the Wisconsin River, crossing it on the west side of Merrill before WIS 107 continues northwest on Grand Avenue. WIS 64 continues east across the Prairie River as 1st Street into downtown. At North Polk Street, WIS 64 splits into two one-way streets; eastbound traffic continues for about seven blocks on East 1st Street, while westbound traffic takes East 2nd Street past the post office, Prairie River Middle School, and on to North Polk Street. Two blocks east of the Lincoln County Courthouse at Center Avenue (also known as County Highway K), WIS 64 turns south for one block and back to East Main Street. It then continues east out of the city to US 51 at exit 208.