,
Bighorn Mountains, Wyoming US 16 originally connected
Detroit with Yellowstone National Park, including a ferry link across
Lake Michigan between
Muskegon, Michigan, and
Milwaukee, Wisconsin aboard
SS Milwaukee Clipper. In Michigan, the route was in use long before automobiles and was known to white settlers as the Grand River Road, and prior to the designation of U.S. Highways in 1926, had been designated as M-16 in the 1920s from Detroit to south of Muskegon. In 1938, reflectorized discs were placed on US 16 every from Detroit to
Lansing, resulting in fewer nighttime traffic accidents. Other states would later do the same on their roads. US 16 initially crossed the
South Dakota–
Wyoming state line west of
Spearfish.
U.S. Highway 216 (
US 216) was commissioned in 1930 as a loop off US 16 to the south between
Rapid City and
Moorcroft, crossing the state line west of
Custer. In 1934, US 16 was moved to the US 216 alignment, while the former US 16 became part of an extension of
US 14. In Michigan, most of US 16 was superseded by
I-96 and a segment of Grand River Avenue in Detroit ultimately became
M-5. US 16 was later decommissioned in
Wisconsin,
Minnesota, and eastern South Dakota to its present termini. Between Rapid City and
Dexter, Minnesota, it has been supplanted by I-90. In
Faribault County, Minnesota, the highway took on another number as there was already a county highway numbered 16. Residents of the county continued referring to the road as "16" or "old 16" and eventually the county renumbered it as County Road 16 (CR 16). From the county's western border with Martin County, US 16 continued east through the city of
Blue Earth as part of 1st Street and Leland Parkway until it briefly combines with
US 169/Grove Street. south of that point at the intersection of Grove and 7th streets, CR 16 followed 7th Street and continued east to the border of
Freeborn County. Most of the stretch through Faribault County was a relatively narrow two-lane highway with wide gravel shoulders that has been widened at least two times since US 16 was decommissioned. East of Dexter, it is now
Minnesota State Highway 16 and
State Trunk Highway 16 in Wisconsin. In South Dakota, it was replaced by various state highways (including
South Dakota Highway 38, or SD 38, and
SD 248) and county roads: generally, in
West River, the old alignment was transferred to county responsibility entirely, while, in
East River, it remained a state-maintained highway. An older
US 16A in South Dakota has become
SD 240. In South Dakota in 2009, the
South Dakota Department of Transportation designated US 16/
US 385 between Custer and
Hill City, which passes by the
Crazy Horse Memorial, now being carved in the
Black Hills, as the Crazy Horse Memorial Highway. This segment of US 385 is also a part of the
George Hearst Memorial Highway. ==Major intersections==