Did you know that the Indian River lagoon on The Atlantic coast of Florida is really a group of three lagoons? Yes that’s true. Together the Mosquito Lagoon, Banana River and Indian River make up the Indian River Lagoon. The Indian River Lagoon or estuary is separated from the Atlantic coast by the barrier islands. The Indian River Lagoon is 156 miles long, it extends from Ponce De Leon Inlet in Volusia County, to the southern border of Martin county. The Indian River Lagoon is connected to the ocean (5 comments)