view-showing-area-for-camping-at-the-hillsborough-river-state-park-thonotosassa-florida_7132199669_o View showing area for camping at the Hillsborough River State Park: Thonotosassa, Florida Date: ca. 1970s General note: The Hillsborough River State Park opened in 1938 as one of Florida's first state parks. It is divided by the swiftly flowing Hillsborough River. Fort Foster, a replica of an 1837 fort from the Second Seminole War, is located on the park grounds, adjacent to the river. No tags for this post.