​IOLA, a city and the county-seat of Allen county, Kansas, U.S.A., on the Neosho river, about 100 m. S. by W. of Kansas City. Pop. (1890) 1706; (1900) 5791, of whom 237 were foreign-born and 207 were negroes; (1905) 10,287; (1910) 9032. It is served by the Atchison, Topeka & Santa Fé, the Missouri Pacific and the Missouri, Kansas & Texas railways. It is pleasantly situated in a level valley where there is a great abundance of natural gas and some fine building stone. The city has large zinc smelters and zinc rolling-mills, a foundry, machine shops, and manufactories of cement, sulphuric acid and brick. The municipality owns and operates its waterworks, gas plant and electric-lighting plant. Iola was founded in 1859 by a company whose members were dissatisfied with the location of the county-seat at Humboldt. It became the county-seat in 1865, was chartered as a city of the third class in 1870 and became a city of the second class in 1898. The rapid growth of the city dates from the discovery of natural gas here, on Christmas Day 1893.