Arkansas is one of the states comprising the United States of America. It joined the Union as 25th member on June 15, 1836. Arkansas's area is 53,187 square miles (137,754 square kilometers) and its estimated population is 2,855,390 (in 2008). Its neighbors are Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma to the west.
The state's capital is Little Rock, which is the urban and economic center of the state. The city became known internationally when in 1957 federal troops entered the town to maintain order after the state militia tried to prevent the desegregation of one of the city's high schools.