city, seat (1913) of Madison county, southeastern Idaho, U.S. Founded by Mormon farmers led by Thomas Ricks in 1883, the city lies in the irrigated agricultural district of the Snake River plain and is a centre of grain and dairy production. Two-thirds of the city was destroyed on June 5, 1976, when the 310-foot- (94-metre-) high earthen Grand Teton Dam collapsed, spilling 80 billion gallons of water across the plain and forcing the evacuation of more than 300,000 Idahoans. Eleven people died in the flood. The city is the seat of Brigham Young University-Idaho (1888). It also hosts the Idaho International Folk Dance Festival. Inc. 1883. Pop. (1990) 14,302; (2000) 17,257.