State Route 4 (SR 4) is a 62.27-mile-long (100.21 km) state highway, serving the southwestern region of the U.S. state of Washington. The highway, officially known as the Ocean Beach Highway, travels east along the Columbia River from U.S. Route 101 (US 101) at Johnston's Landing through Pacific, Wahkiakum and Cowlitz counties to an interchange with Interstate 5 (I-5) in Kelso.