t.Louis. Other large cities are Springfield, Independence, Saint Joseph, and Columbia. Two-thirdsof Missourians live in metropolitan areas, with one-third of those in the 19 cities with populationsof 25,000 or more. Between 1980 and 1990 the population of Missouri increased by more than4%, and Missouri was among the faster-growing states in the Midwest but remained below thenational growth average.Missouri has one of the nation's highest percentages of persons over 65 years of age. Blacks,concentrated in the large cities, constitute 10.7% of the state's population. The religious affiliationof Missourians is diverse. Roman Catholics are the largest single religious group, but Protestants,representing many denominations, form the majority of church members.Land RegionsMissouri has three major physiographic regions: the Ozark Highland, the Plains, and theMississippi Alluvial Plain. The Ozark Highland has an average elevation of about 305 m (1,000ft); it covers the southern portion of the state from St. Louis and Jefferson City on the MissouriRiver to Oklahoma and Arkansas. The region is famous for more than 5,000 caves and many largesprings. One, Big Spring, in the south central part of the state, is among the largest springs in theUnited States. The Ozarks retain the rolling surface of a plateau near Springfield and in some ofthe central areas, but elsewhere swift-flowing streams have dissected the plateau, forming steep,narrow-crested hills. Relief reaches 230 m (750 ft) in the most rugged areas (see OzarkMountains).North and west of the Ozarks is the Plains region, rising gradually from 200 m (650 ft) near St.Louis to more than 380 m (1,250 ft) in the extreme northwest. During the past half-million yearsPleistocene glaciers extended as far south as the Missouri River, covering northern Missouri withglacial till. Parts of the northeast are nearly flat, but in most places postglacial erosion by streamshas resulted in hills and valleys. In...
