Indiana, constituent state of the United States of America. states in terms of total area and, except for Hawaii, is the smallest state west of the Appalachian Mountains.The state sits, as its motto claims, at “the crossroads of America.” It borders Lake Michigan and the state of Michigan to the north, Ohio to the east, Kentucky to the south, and Illinois to the west, making it an integral part of the American Midwest. With a name that is generally thought to mean “land of the Indians,” Indiana was admitted on December 11, 1816, as the 19th state of the union. Today Indiana’s economy is based primarily on services, manufacturing, and, to a much lesser extent, agriculture.In addition, average daily temperatures are warmer in the fall and cooler in the spring (April through June) as a result of this “lake effect.” Indiana is part of a belt of Midwestern states with an unusually high frequency of severe storms.Spring, with its generally erratic and unstable weather, is the season with the greatest number of tornadoes.
Aside from white-tailed deer, the population of which has been revived largely as a result of government conservation efforts, smaller mammals such as opossums, skunks, raccoons, rabbits, moles, shrews, and bats are abundant throughout the state.Most of the state’s surface was modified by glacial action, leaving a vast quantity of excellent soil material and extensive deposits of sand, gravel, glacial till, and loess.The more-eroded southern part of the state gives way to the central plain, an extremely fertile agricultural belt with large farms, and then to the mostly flat glacial lake basin and moraine (rocky glacial debris) region of northern Indiana.Steady growth of agriculture, urban areas, and industry and the consequent pollution have taken a toll on natural life, however.Pollution of both air and water has been particularly severe near the industrial areas along the southern tip of Lake Michigan.In January, daily temperatures in Jeffersonville, on the Ohio River in the south, usually rise from the low 20s F (about –6 °C) into the low 40s F (about 4 °C), while in South Bend, near Lake Michigan in the north, temperatures typically range from the mid-10s F (about −9 °C) to the low 30s F (about −1 °C).In July, temperatures in both the north and the south normally drop into the mid-60s F (about 17 °C) and rise into the mid- to upper 80s F (28–32 °C) daily.The general slope and drainage pattern is toward the south and southwest, though an almost imperceptible groundswell in the northeast forms a watershed between the St. The Wabash, the Ohio, and the east and west forks of the White River form part of the Mississippi basin. Joseph River meanders into Lake Michigan, while in the east the Maumee flows northeastward into Lake Erie.The northern half of the state is dotted with many small glacial lakes, including several of the state’s largest.The climate of northwestern Indiana is modified greatly by its presence in the lee of Lake Michigan.Cold air passing over the warmer lake water in fall (October through December) and winter (January through March) induces heavy precipitation, and winter snowfall especially is several times greater than in other parts of the state.