After the Ohio country became a US territory in 1785, Virginians, Connecticut Yankees, and New Jerseyites began arriving in significant numbers; tens of thousands of settlers from New England, Pennsylvania, and some southern states thronged into Ohio in subsequent decades. The great migration from the eastern states continued throughout most of the 19th century, and was bolstered by new arrivals from Europe. The Irish came in the 1830s, and many Germans began arriving in the 1840s. Another wave of European immigration brought about 500,000 people a year to Ohio during the 1880s, many of them from southern and eastern Europe. Former slaves left the South for Ohio following the Civil War, and a larger migratory wave brought blacks to Ohio after World War II to work in the industrial cities. In the 1910s, many emigrants from Greece, Albania, and Latvia settled in Akron to work in the rubber industry.
The industrialization of Ohio in the late 19th and the 20th centuries encouraged the migration of Ohioans from the farms to the cities. The large number of Ohioans who lived in rural areas and worked on farms declined steadily after 1900, with the farm population decreasing to under 1,000,000 during World War II and then to fewer than 400,000 by 1979. A more recent development has been the exodus of urbanites from Ohio's largest cities. From 1970 to 1990, Cleveland lost 245,000 residents, Cincinnati 90,000, Dayton 61,000, Akron 52,000, and Toledo 50,000. Columbus was the only major city to gain residents—93,000—during this period. Ohio lost more than one million people through migration during the period 1970–83. Net migration loss for the state from 1985 to 1990 came to 72,000. Between 1990 and 1998, Ohio had a net loss of 144,000 in domestic migration and a net gain of 48,000 in international migration. In 1998, 7,697 foreign immigrants arrived in Ohio; of these, the greatest number, 900, came from India. The state's overall population increased 3.3% between 1990 and 1998. In the period 1995–2000, 588,650 people moved into the state and 705,590 moved out, for a net loss of 116,940, many of whom (90,833) moved to Florida.