The Hillsborough River empties into Tampa Bay, which is the most important open up-water estuary in Florida. An estuary is a partly enclosed body of water where fresh water from rivers and streams mixes with salty seawater. The St. Johns then flows into what is named the river’s upper basin. https://riversinsouthflorida21986.wizzardsblog.com/33485588/best-rivers-in-florida-to-kayak-secrets