WIS 23 joins WIS 73 on the west side of Princeton. They head east along Main Street then south along Fulton Street before leaving the city. They continue to be cosigned heading east for another 3 miles before WIS 73 turns south to head to Randolph and Columbus. WIS 23 passes north of Green Lake and is joined by WIS 49 northeast of the city. A business route of WIS 23 exists, using Lawson Dr in Green Lake. The highway concurrency of 23 and 49 enters Fond du Lac County two miles (3 km) east of Green Lake. 23 and 49 continue heading southeast to Ripon. On the southeast side of Ripon, WIS 49 South, along with WIS 44 South, cuts south toward Brandon, Markesan and Waupun. WIS 44 has a short cosign with WIS 23 on the eastside of Ripon before it cuts north to Pickett and Oshkosh. WIS 23 continues east, crossing WIS 26 in Rosendale. As the highway enters Fond du Lac, it junctions with I-41 and becomes Johnson St., the main east–west thoroughfare through the city. WIS 23 crosses US 45 in the city center and US 151 on the east side. After a twelve-mile (19 km) rural stretch from Fond du Lac, WIS 23 enters Sheboygan County The route passes near Greenbush about four miles (6 km) into the county, then becomes a freeway about two miles (3 km) northwest of Plymouth, without exit numbering. Around Plymouth, access is provided to CTH C, WIS 67, CTH E, and WIS 57. In Sheboygan Falls, an interchange is present at WIS 32. WIS 23 junctions with I-43 at a cloverleaf interchange just west of Sheboygan. The freeway segment ends a mile east of Interstate 43 at North 25th Street, with an exit at Taylor Drive. WIS 23 follows Kohler Memorial Drive and the straight-line portion of Erie Ave into the city, continuing as a divided highway until three blocks before its termination at WIS 28 south and WIS 42 north. Erie Avenue continues undesignated for about .9 of a mile east, until coming to an end at a cul-de-sac a block west of Lake Michigan, overlooking Broughton Drive.