State Route 243 (SR 243) is a 28.26-mile (45.48 km) long state highway in the U.S. state of Washington, located entirely within Grant County and serving Desert Aire, Mattawa, Beverly and Vantage. The roadway, which roughly parallels the Columbia River, begins at SR 24 southwest of Desert Aire and continues north past the Priest Rapids Dam and Wanapum Dam to SR 26 south of Vantage. The road was established originally as a branch of Secondary State Highway 7C (SSH 7C) in 1957.