State Route 124 (SR 124) is a state highway in Walla Walla County, Washington, United States. It spans 45 miles (72 km) from Burbank in the west to Waitsburg in the east, intersecting U.S. Route 12 (US 12) at both ends. The highway generally follows the Snake and Touchet rivers and intersects SR 125 near Prescott.

U.S. Route 12 is a major east–west U.S. Highway, running from Aberdeen, Washington, to Detroit, Michigan. It spans 430.5 miles (692.8 km) across the state of Washington, making it the second longest highway in the state. It is also the only numbered highway to span the entire state from west to east, starting near the Pacific Ocean, and crossing the Idaho state line near Clarkston. It crosses the Cascade Range over White Pass, south of Mount Rainier National Park. Portions of it are concurrent with Interstate 5 (I-5) and Interstate 82 (I-82), although the majority of the route does not parallel any interstate highway.