when was u.s. route 25 constructed?
November 11, 1926
U.S. Route 25 in Michigan
Created with the initial US Highway System on November 11, 1926, US 25 replaced several previous state highway designations.
wiki:16569774
U.S. Route 25 in Michigan [SEP] Introduction
Created with the initial US Highway System on November 11, 1926, US 25 replaced several previous state highway designations. Some of the preceding highways followed roadways created in the 19th and the early 20th centuries. It initially was only routed as far north as Port Huron; the northern extension to Port Austin happened in 1933. By the end of the 1950s, the entire route was paved. Starting in the early 1960s, segments of I-75 and I-94 were built, and US 25 was shifted to follow them south of Detroit to Port Huron. A business loop was created when the main highway bypassed downtown Port Huron, and then in 1973, the entire designation was removed from the state.