[1] In Milwaukee the original routing of US 41 used Lisbon Avenue east to North 27th Street, then south along that road to the Illinois state line.

WisDOT rerouted US 41 along I-94 from the Stadium Interchange to the Illinois state line, removed Layton Boulevard north of Forest Home Avenue from the state highway system and gave Layton Boulevard and 27th Street south of Forest Home Avenue the designation of WIS 241 in a compromise to avoid expansion of the original route.

The old US 41 freeway section south of I-94 to National Avenue (which was realigned to accommodate the construction of American Family Field) was designated WIS 341 but is unsigned.

[2] By 1955, US 41 was relocated from the corridor of today's WIS 175 and its successors to a nearby expressway in Winnebago, Fond du Lac, Dodge, Washington, Waukesha, and Milwaukee Counties.

[3] Appleton also saw US 41 realignments over the course of time, beginning with the 1937 two-lane bypass (along the present freeway route) from Neenah northerly to a T-intersection with US 10 (today's Wisconsin Avenue, WIS 96).

In 1940, US 41 was extended northerly from the T-intersection at US 10 for one mile (1.6 km), before making a large sweeping curve onto present day Northland Avenue to join back up with the previous bypass at Richmond Street.