Hillsborough River (Florida)

Hillsborough River
Country	United States
State	Florida
Counties	Pasco, Hillsborough
District	SWFWMD
Tributaries
- left	Blackwater Creek, Flint Creek
Cities	Temple Terrace, Tampa
Source	Green Swamp
- location	Branchborough, Florida
- coordinates	28°16′28″N 84°05′38″W / 28.27444°N 84.09389°W / 28.27444; -84.09389
Mouth	Hillsborough Bay
- location	Tampa, Florida
- coordinates	27°56′16″N 82°27′43″W / 27.93778°N 82.46194°W / 27.93778; -82.46194Coordinates: 27°56′16″N 82°27′43″W / 27.93778°N 82.46194°W / 27.93778; -82.46194
Length	59 mi (95 km)
Basin	740 sq mi (1,917 km2)
Hillsborough River watershed

The Hillsborough River is a river located in the state of Florida in the USA. It arises in the Green Swamp near the juncture of Hillsborough, Pasco and Polk counties, and flows 59 miles (95 km) through Pasco and Hillsborough Counties to an outlet in the city of Tampa on Tampa Bay. The name Hillsborough River first appeared on a British map in 1769. At the time, the Earl of Hillsborough was the British Secretary of State for the Colonies, and thus controlled the pensions of the surveyors working in the American colonies, which included East Florida.

Geological data suggests that the Hillsborough River has been flowing for about 27,000 years. Humans first made their way to this area 12,000 - 15,000 years ago.

In the late 18th century the watershed of the Hillsborough River was a land covered by a rich, old growth forest. Majestic bald cypress, longleaf pine, and sand live oak were hundreds of years old (and in the case of cypress, thousands of years old). In the mid to late 19th century to about 1913 the watershed of this old growth forest began to be logged. As a result of this lumbering activity, most of the trees within the Hillsborough River basin are now less than one hundred years in age. The harvesting of the old growth trees altered the ecosystems they dominated. Trees such as water ash and water locust were able to quickly grow in the sun-lit spaces created when bigger trees were removed. The riverine swamp forest as it exists today has a much different ecology than the ecosystem that had existed along the Hillsborough for the previous ten to fifteen thousand years.