U.S. Highway 218 (US 218) is an original United States Highway that was created in 1926. Although technically a spur of US 18, US 218 neither begins nor ends at US 18, but overlaps US 18 for eight miles (13 km) near Charles City, Iowa. US 218 begins at U.S. 136 in downtown Keokuk and ends 319 miles (513 km) away at Interstate 35 (I-35) and US 14 at Owatonna, Minnesota. A large portion of US 218 in Iowa is part of the Avenue of the Saints, which connects St. Louis, Missouri, and Saint Paul, Minnesota.

U.S. Highway 18 (US 18) is an east–west United States Numbered Highway in the Midwestern United States. The western terminus is in Orin, Wyoming, at an interchange with Interstate 25 (I-25). Its eastern terminus is in Downtown Milwaukee, Wisconsin. US 18, however, runs concurrent with other U.S. Highways from its western terminus to Mule Creek Junction, Wyoming. US 18 is one of the original U.S. Highways of 1926. The US 18 designation was originally proposed for a road in Michigan from Grand Haven east to Detroit. This roadway was eventually designated as US 16.