Henrys Fork (Snake River tributary)

Henrys Fork
Henrys Fork in eastern Idaho
Henrys Fork upper drainage
Location of the mouth of Henrys Fork in Idaho
Location
Country	United States
State	Idaho
Counties	Fremont County, Idaho, Madison County, Idaho
Physical characteristics
Source
• location	near Island Park, Fremont County, Idaho
• coordinates	44°29′34″N 111°16′58″W / 44.49278°N 111.28278°W / 44.49278; -111.28278[1]
• elevation	6,397 ft (1,950 m)[2]
Mouth	Snake River
• location	southwest of Rexburg, Madison County, Idaho
• coordinates	43°45′10″N 111°57′28″W / 43.75278°N 111.95778°W / 43.75278; -111.95778[1]
• elevation	4,800 ft (1,500 m)[1]
Length	127 mi (204 km)[3]
Basin size	3,212 sq mi (8,320 km2)[4]
Discharge
• location	near Rexburg[5]
• average	2,096 cu ft/s (59.4 m3/s)[5]
• minimum	183 cu ft/s (5.2 m3/s)
• maximum	79,000 cu ft/s (2,200 m3/s)

Henrys Fork is a tributary river of the Snake River, approximately 127 miles (204 km) long,^[3] in southeastern Idaho in the United States. It is also referred to as the North Fork of the Snake River. Its drainage basin is 3,212 square miles (8,320 km²), including its main tributary, the Teton River.^[4] Its mean annual discharge, as measured at river mile 9.2 (Henrys Fork near Rexburg) by the United States Geological Survey (USGS),^[6] is 2,096 cubic feet per second (59.4 m³/s), with a maximum daily recorded flow of 79,000 cubic feet per second (2,240 m³/s), and a minimum of 183 cubic feet per second (5.18 m³/s).^[5] It is normally transcribed without an apostrophe.

The river is named for Andrew Henry,^[7] who first entered the Snake River plateau in 1810. Employed by the Missouri Fur Company, he built Fort Henry on the upper Snake River, near modern St. Anthony, but abandoned this first American fur post west of the continental divide the following spring.^[8]