U.S. Route 12 or US 12 is an east–west United States highway, running from Grays Harbor on the Pacific Ocean, in the state of Washington, to downtown Detroit, for almost 2,500 miles (4,000 km). As a thoroughfare, it has mostly been supplanted by I-90 and I-94, but remains an important road for local and regional travel.

The highway begins in downtown Detroit, at the corner of Michigan and Woodward Avenue. Its western terminus is in Aberdeen, Washington at an intersection with US 101.