Rio Dell is a city in Humboldt County, California. Rio Dell is located on the west bank of Eel River 1 mile north of Scotia, at an elevation of 161 feet. The population is 3,363. This region experiences warm (but not hot) and dry summers, with no average monthly temperatures above 71.6. The first post office at Rio Dell opened in 1876. Rio Dell incorporated in 1965. Rio Dell was connected to Scotia by a ferry provided by the lumber mill, and a suspension bridge built in 1914. Rio Dell is the host of Wildwood Day’s in July. Wildwood Days have events such as a car cruise, Firefighter Muster, Music Festival and Wildwood Day’s Parade.