The St. Johns River ((スペイン語:Río de San Juan)) is the longest river in the U.S. state of Florida and its most significant for commercial and recreational use. At long, it winds through or borders twelve counties, three of which are the state's largest. The drop in elevation from headwaters to mouth is less than ; like most Florida waterways, the St. Johns has a very low flow rate and is often described as "lazy".〔Whitney, p. 215.〕 It is believed to be one of the few rivers that flow north, although there are hundreds of the kind worldwide. Numerous lakes are formed by the river or flow into it, but as a river its widest point is nearly 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.〔Belleville, p. xxi.〕
The St. Johns drainage basin of includes some of Florida's major wetlands.〔(The St. Johns River: Nominated as an American Heritage River ), Environmental Protection Agency. Retrieved on July 17, 2009.〕〔Whitney, p. 136.〕 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 Paleo-indians, 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; 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, named one of 14 American Heritage Rivers in 1998, was included on a list of America's Ten Most Endangered Rivers in 2008.〔Ball, David (April 14, 2008).(St. Johns River Makes 'Endangered' List ), ''Jacksonville Financial and Daily Record'', Retrieved on July 17, 2009.〕 Restoration efforts are under way for the basins around the St. Johns as Florida continues to deal with population increases in the river's vicinity.
== Geography and ecology ==
Starting in Indian River County and meeting the Atlantic Ocean at Duval County, the St. Johns is Florida's primary commercial and recreational waterway. It flows north from its headwaters, originating in the direction of the Lake Wales Ridge, which is only slightly elevated at above sea level. Because of this low elevation drop, the river has a long backwater. It ebbs and flows with tides that pass through the barrier islands and up the channel.〔McCarthy, p. 2.〕 Uniquely, it shares the same regional terrain as the parallel Kissimmee River, although the Kissimmee flows south.〔
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