200px|right|thumb|the edisto river watershed the edisto river is the longest free flowing blackwater river in north america, flowing over 250 meandering miles from its sources in saluda and edgefield counties, to its atlantic ocean mouth at edisto beach, south carolina. it rises in two main tributaries (north fork & south fork) from springs under the sandhills region of west central south carolina, just to the south of the piedmont fall line. it is the longest and largest river system completely contained by the borders of south carolina. its name comes from the edisto subtribe of the cusabo indians. near the coast, part of the river was once known as the ponpon river. the dawhoo river (sometimes dawho, or dawhoe) connects the edisto to the north edisto river, also the confluence of the wadmalaw and the toogoodoo rivers, where they meet the atlantic ocean. between the coast and the dawhoo river, the river is known as the south edisto river.report of the chief of engineers u.s. army, 1881, volume ii, page 1140.  the edisto system flows through only one major town or city, orangeburg, the location of edisto gardens (on the north fork). the river system, being blackwater throughout its entire length, flows through highly intermittent bottom swampland. during an excessively rainy season, the river will leave its main channel, with its flow basin increasing to over a mile or more of total width. the lower edisto basin forms a crucial part of the ace basin, an area that encompasses its bottomlands confluence with the ashepoo and combahee river basins. a major tributary is four holes swamp, which is unique in that it has no single defined channel, but rather a network of braided channels. ==conservation== ===wildlife=== common fish by biomass in the freshwater portions of the edisto include spotted sucker (minytrema melanops), bowfin (amia calva), flat bullhead (ameiurus platycephalus), largemouth bass (micropterus salmoides), common carp (cyprinus carpio), longnose gar (lepisosteus osseus), and american eel (anguilla rostrata).{{cite web |url=http://www.gpo.gov/fdsys/pkg/czic-ql614-83-s68-f57-1995/html/czic-ql614-83-s68-f57-1995.htm |title=fishes of the edisto river basin |last1=marcy, jr. |first1=barton c. |last2=o'brien-white |first2=suzanne k. |year=1995 |work= |publisher=s.c
Landforms_of_Charleston_County,_South_Carolina Landforms_of_Colleton_County,_South_Carolina Landforms_of_Orangeburg_County,_South_Carolina Rivers_of_South_Carolina