In this section

The St. Johns
River Home

Facts about the St. Johns River

Fragile ecology

Water quality

Tour of the St. Johns River

Facts about the St. Johns River

The St. Johns River in Brevard County.

General facts

The St. Johns River is an ancient intracoastal lagoon system. As sea levels dropped, barrier islands became an obstacle that prevented water from flowing east to the ocean. The water collected in the flat valley and slowly meandered northward, forming the St. Johns River.

• The St. Johns River is the longest river in Florida — 310 miles. It is one of the few rivers in the United States that flows north.
• The square mileage of the St. Johns River’s drainage basin in 8,840.
• The river gets its tea color from tannins, a natural color caused by decaying plant material.
• The land area that drains into a water body is called a drainage basin, “watershed.” The St. Johns River is divided into three drainage basins.
• Because the river flows north, the upper basin is the area to the south that forms its marshy headwaters in Indian River and Brevard counties. The middle basin is the area in central Florida where the river widens, forming lakes Harney, Jesup, Monroe and George. The lower basin is the area in northeast Florida from Putnam County to the river’s mouth in Duval County, where the river empties into the Atlantic Ocean.
• The width of the river varies. It is a flat marsh at its headwaters and averages about two miles in width between Palatka and Jacksonville. It widens to form large lakes in central Florida.
• The total drop of the river from its source in marshes south of Melbourne to its mouth in the Atlantic near Jacksonville is less than 30 feet, or about one inch per mile, making it one of the “laziest” rivers in the world.
• Because the river flows slowly, it is difficult for the river current to flush pollutants.
• Major pollution sources include discharges from wastewater treatment plants and stormwater runoff from urban and agricultural areas. This runoff carries pesticides, fertilizers and other pollutants into canals, ditches and streams that lead to the river. River pollution is concentrated around urban areas.
• Salt water enters the river at its mouth in Jacksonville. In periods of low water, tides may cause a reverse flow as far south as Lake Monroe — 161 miles upstream from the river’s mouth.
• Major tributaries, or smaller streams and rivers that flow into the St. Johns River, include the Wekiva River, the Econlockhatchee River and the Ocklawaha River.

The Memorial Bridge between Palatka and East Palatka.

Historical facts

• Before European involvement in North America, the Timucuan Indians called the St. Johns River Welaka — or river of lakes.
• In the early 1500s, Spanish seamen called the river Rio de Corrientes — or river of currents.
• In 1562 — almost 50 years before the settlement in Jamestown — the French established Fort Caroline on a high bluff overlooking a river they called Riviere de Mai (River of May) because they arrived there on May 1.
• In 1565, Spanish soldiers marched north from St. Augustine, captured Fort Caroline and slaughtered the French. The Spanish renamed the river San Mateo to honor the saint whose feast followed the day they captured the river.
• Later, the river was renamed Rio de San Juan after a mission near its mouth named San Juan del Puerto. The English translation of the name Rio de San Juan — St. Johns River — lasted through English, Confederate and American possession of the river and remains today.
• Soon after England acquired Florida in 1763, King George III sent botanist John Bartram to explore Florida. His son, William Bartram, stayed in Florida and published his book Travels in 1791. It describes his exploration of the river as far south as Lake Harney.
• In the 1800s, steamboats made the St. Johns River a popular winter destination for northerners. By the 1860s, several steamers were making weekly round trips from Charleston and Savannah to Jacksonville and Palatka, and other settlements.
• In the 1900s, miles of floodplain were drained to make room for indigo, sugar cane, citrus and other profitable crops. Encroachment through draining of the headwater marshes at the river’s southern end was neither planned nor controlled. More than 70 percent of the marsh was claimed for agricultural and urban uses.
• In 1954, Congress authorized flood-control works in the southern part of the St. Johns River. To store water and to move floodwaters, large reservoirs and canals were designed by the U.S. Army Corps of Engineers (Corps).
• The Corps’ project was halted in the 1970s. In 1974, the project was deemed unacceptable for environmental reasons.
• In 1980, a redesigned project by the St. Johns River Water Management District favored restoring wetlands to hold and release floodwaters and managing water levels to simulate natural marsh conditions. Since the project began, the District has restored more than 150,000 acres of original marsh, an area about the size of Delaware.