North of 53rd Street, the two directions rejoin as one road. The route ends at the I-80 interchange on the northern side of town. The entire route is inventoried as Iowa Highway 461, but it not signed as such. The business route through Maquoketa follows Main Street through the downtown business district, and Iowa Highway 64 along Platt Street. The route is unsigned, aside from a few circle "City Route 61" signs along Main Street. Although not designated until 1998, Main Street had essentially served as a "Business 61" since at least the mid-1970s, when U.S. 61 was moved to a two-lane bypass around the south and west parts of the city. The two-lane segment was upgraded to four lanes in the summer of 1996, as part of a massive four-lane project of U.S. 61 between Dubuque and De Witt. U.S. Highway 61 Bypass (US 61 Byp.) ran through Baton Rouge, the capital city of Louisiana. It followed the Airline Highway, a four-lane bypass of the downtown area constructed in 1941. The designation remained in effect until about 1963, when its route was assumed by mainline US 61.