Kentucky, a state of the American Union, in the Mississippi Valley; greatest length, E. to W., 400 miles; breadth, N. to S., 175 miles; area, 40,400 sq. m. The eastern and south-eastern parts of the state are mountainous, broken by the Cumberland Mountains (2000-3000 feet) and their offshoots; westward from this region is a plateau sloping gradually toward the Ohio and the Mississippi rivers, which bound the state on the north and west. Large cypress-swamps still exist in the south-west. The Cumberland, Tennessee, Licking, and Kentucky rivers rise among the mountains in the east, and cross the state to the Ohio. Southward from the Ohio River extends a semicircular tract of land of Silurian formation ; here the soil is produced by the disintegration of the fossiliferous blue limestone, and in this, the famous Blue Grass country, the most exhausting crops, such as tobacco and hemp, may be raised continuously for a series of years without materially impairing the productive value of the soil. A somewhat narrow belt of Devonian shale is also very fertile, and the lower strata contain petroleum. The eastern coalfield (10,000 sq. m.) is a prolongation of the Appalachian deposits; the western (4000 sq. m.) belongs to the Illinois tract. The coal is bituminous, and some excellent cannel occurs. The iron ores are of excellent quality, and are found throughout a district of 20,000 sq. m. Galena, building-stones, and salt are obtained. Through the limestone formations the streams have cut deep gorges, and in a region of about 6000 sq. m. much of the drainage is subterranean. The long-continued erosive action of the water has undermined a large part of this region, and produced numerous and often extensive caverns - the best known being the Mammoth Cave (q.v.). Kentucky is densely wooded over two-thirds of its area. Notwithstanding this large proportion of forest land, it has always been one of the leading agricultural states ; it is the principal tobacco-producing state in the union, and breeds excellent stock and racehorses. The chief manufacture is whisky; next the smelting and working of iron. Pop. (1860) 1,155,684; (1880) 1,648,690; (1900) 2,147,174. The largest cities are Louisville (205,000), Covington (43,000), Lexington (26,500), and Paducah (19,500); the capital is Frankfort (9500). Numerous remains indicate that the mound-builders lived here ; the name Kentucky, 'dark and bloody ground,' commemorates the conflicts between various warlike tribes. Included in the original grant to the colony of Virginia, Kentucky in 1790 was made a territory, and in 1792 a state. Though a slave-holding state, it did not secede during the civil war.