Marblemount is a census-designated place (CDP) in Skagit County, Washington, United States. The population was 203 at the 2010 census. It is included in the Mount Vernon–Anacortes, Washington Metropolitan Statistical Area. Original location for the Summer Rock the Art Fest (formerly known as Beaver Fest)
Marblemount is located at 48°32′17″N 121°26′16″W / 48.53806°N 121.43778°W / 48.53806; -121.43778 (48.538154, -121.437844).
According to the United States Census Bureau, the CDP has a total area of 2.5 square miles (6.4 km²), of which, 2.4 square miles (6.1 km²) of it is land and 0.1 square miles (0.3 km²) of it (4.44%) is water.