St. Johns River

The St. Johns River is the longest river in the U.S. state of Florida and its most significant for commercial and recreational use. At 310 miles (500 km) long, it winds through or borders twelve counties, three of which are the state's largest. The drop in elevation from the headwaters to the mouth is less than 30 feet (9.1 m); like most Florida waterways, the St. Johns has a very slow flow rate at a third of a mile an hour (0.5 km/h), and is often described as "lazy". It is one of a small number of rivers in the United States to run north. Numerous lakes are formed by the river or flow into it, but as a river its widest point is nearly 3 miles (4.8 km) across, The narrowest point is in the headwaters, an unnavigable marsh in Indian River County. In all, 3.5 million people live within the various watersheds that feed into the St. Johns River.

With a drainage basin of 8,840 square miles (22,900 km2), the St. Johns is one of the major interior wetlands of Florida. It is separated into three major basins and two associated watersheds for Lake George and the Ocklawaha River, all managed by the St. Johns River Water Management District.

A variety of people have lived on or near the St. Johns, including Archaic people, Timucua, Mocama, French and Spanish settlers, Seminoles, slaves and freemen, Florida crackers, land developers, tourists, and retirees. It has been the subject of William Bartram's journals, Marjorie Kinnan Rawlings' books, and Harriet Beecher Stowe's letters home.

Although Florida was the location of the first permanent European colony in what would become the United States, it was the last U.S. territory on the east coast to be developed, and it remained an undeveloped frontier into the 20th century. When attention was turned to the state, however, much of the land was rapidly overdeveloped in a national zeal for progress. The St. Johns, like many Florida rivers, was altered to make way for agricultural and residential centers. It suffered severe pollution and human interference that has diminished the natural order of life in and around the river.

The St. Johns was named one of 14 American Heritage Rivers in 1998 but was included on a list of America's Ten Most Endangered Rivers in 2008. Restoration efforts are underway for the basins around the St. Johns as Florida continues to deal with population increases in the river's vicinity.