Green Cove Springs is a city in and the county seat of Clay County, Florida, United States. Green Cove Springs is a part of the Jacksonville, Florida Metropolitan Statistical Area. The population was 9,786 at the 2020 census, up from 6,908 at the 2010 census. The city is named after the portion of the St. Johns River upon which it is built. The river bends here, and the area is sheltered by trees that are perennially green.