Underwood is an unincorporated community in Skamania County, Washington, United States. Underwood is located along Washington State Route 14 at the confluence of the White Salmon and Columbia Rivers. It is across the Columbia River from Hood River, Oregon, and 2 miles west of White Salmon, Washington. Underwood has a post office with ZIP code 98651.A post office called Underwood has been in operation since 1900. The community has the name of Amos Underwood, a pioneer settler.