CARLINVILLE, a city of western Illinois, U.S.A., on the Chicago and Alton railroad, 6om. N. by E. of Saint Louis; the county seat of Macoupin county. The population in 1930 was Natural gas is found in the vicinity, and in a normal year the county mines over 6,000,000 tons of coal. The city manufac tures brick, tile and monuments. It was settled about 1828 and incorporated as a city in 1865.