"M" is for Marlboro County [480 square miles; population 28,818]. Marlboro County was formed in 1785 and named for the Duke of Marlborough. Its boundaries have remained virtually unchanged since then: bounded on the west by the Great Pee Dee River; on the north and northeast by North Carolina; and on the Southeast by Dillon County. Prior to European settlement, Cheraw Indians lived in the area. During the 1730s, generous land policies attracted Welsh settlers from Pennsylvania. The county's rich loamy soils have produced a variety of crops including corn, indigo, and cotton. In the 1880s, the arrival of the railroad, the opening of the Bank of Marlboro, and the construction of cotton mills helped diversify the local economy. In 1885, a new courthouse was built in Bennettsville, the county seat of Marlboro County.