SR 24 was added to Washington's state highway system in 1937 as Secondary State Highway 11A (SSH 11A), which traveled from Primary State Highway 3 (PSH 3) and US 410 in Yakima to PSH 11 and US 395 in Connell. The highway was preceded by several unpaved roads built by county governments along the corridor by the 1910s, including a road across the Moxee and Black Rock valleys, a ferry across the Columbia River at White Bluffs, and a road continuing to Connell, bypassing Othello.