The Florida Intracoastal Waterway which runs from Boston to Florida and along the Atlantic East Coast and Gulf Coast is a series of canals, rivers, bays and inlets which runs parallel to the shoreline. I recently visited St Augustine, Fla. and saw part of the coastal waterway that runs through town and along the Atlantic Ocean coastline. The river closest to the ocean is the Salt River seen from the top of the lighthouse which connects with the Intracoastal Waterway which lies further inland.
Some parts of the waterway is naturally made with islands and rivers separated by the mainland and some parts were made by people such as engineers, town officials and land developers. The concept of building a inland/coastal waterway in Florida began in 1885 when the Florida Canal Co. began to dredge a canal between Mosquito Lagoon and Indian River which is just north of Merritt Island. USA Today published an article about the Intracoastal Waterway which described its purposes, location and early designers.
Some parts of the waterway is used for commercial purposes to transport ocean freight, marine cargo and some parts of it are used exclusively for recreational purposes. Fort Lauderdale’s Intracoastal Waterway which lies between a barrier island and the mainland is called Millionaires Row because of the expensive homes and boats that line the waterway. There are many people who take their boats up through the Intracoastal Waterway for several states. In my area of SW Florida the Caloosahatchee River runs from the Gulf of Mexico to Lake Okeechobee inland and then through the St. Lucie River until its connects with the waterway on the east coast. Wikipedia also has a lot of interesting facts about the Intracoastal Waterway.