Our area's earliest inhabitants were Native Americans who lived, hunted, and traded along the Great Pee Dee River. The first settlers were Welsh Baptists who immigrated from Pennsylvania in 1737, making their homes near the riverbank in the area that would become known as Welsh Neck. Marlborough was originally part of the Old Cheraws District, which also included present-day Chesterfield and Darlington counties. Both Patriots and Loyalists lived here during the American Revolution, and Marlboro was the site of several skirmishes.
In 1785, the Cheraws District was split, and Marlboro County was created. The original courthouse was built near the Pee Dee River, and a community called Carlisle grew up around it. In 1819, the courthouse was moved to a more central location, and the town of Bennettsville was born. During the mid-19th century, communities throughout the county began around churches, principal roads, and at the county's most famous mineral springs, Blenheim. Planters and farmers found Marlboro County's loamy soils excellent for farming.
As the Civil War was waning, Marlboro County was host to every unit of General William T. Sherman's Union Army when it left Cheraw, crossed the Great Pee Dee River, and traveled through this county in route to its final engagement in North Carolina. Although some frame buildings, warehouses, and a few downtown structures were burned, Marlboro County's courthouse was spared, giving this county one of the state's oldest complete sets of county records.
D.D. McColl brought the first railroad to the county during the 1870s, the first bank during the 1880s, and cotton mills to McColl and Bennettsville during the 1890s and early years of the 20th century. The arrival of the railroad did a great deal for the development of the county as it made it possible to transport Marlboro-grown cotton to markets and mills far from her borders. During this time, McColl, Clio, Tatum, Blenheim and Bennettsville grew with mercantile stores, doctors' offices, and grocery stores. Postal service improved drastically and schools were built all across the county.
Marlboro County Courthouse, 1850s