Oshkosh (ŏshˈkŏshˌ) [key], city (1990 pop. 55,006), seat of Winnebago co., E Wis., on Lake Winnebago where the Upper Fox River enters; inc. 1846. Its manufactures include automobile parts, wood products, electrical equipment, and machinery; its renowned bib-overalls factory closed in 1997. Oshkosh is a summer resort, noted for its annual experimental aircraft convention. Father Allouez visited the site in 1670; French explorers traveled there in the 18th cent.; and a French fur-trading post was set up in the early 19th cent. Oshkosh grew as a lumber town. The downtown area was destroyed by fire in 1875. A branch of the Univ. of Wisconsin is there.