Coffeyville (kôˈfēvĭlˌ, kŏfˈē–) [key], city (1990 pop. 12,917), Montgomery co., SE Kans., on the Verdigris River near the Okla. line, in a farm and oil area; inc. 1872. It is a trading and distribution center with dairying, flour milling, manufacturing (mostly machinery), and oil refining. With the coming of the railroad (1870), Coffeyville grew as a cattle-shipping point. Oil and natural gas were discovered in the area in 1902. The city was the scene (1892) of a famous shoot-out with the notorious Dalton gang during an attempted bank robbery. Of interest are the Dalton graves and the Dalton Museum.