Oakland was the family home of George R. Gaither, a successful Baltimore merchant who purchased the property in 1838. His son, George R. Gaither, Jr., served as captain of the Howard Dragoons, a local militia unit of mounted infantrymen made up largely of landed gentry from throughout the county, many of them slave owners. They drilled here in the movements of mounted combat and staged parades in Ellicott's Mills on special occasions such as Independence Day. After the Baltimore Riot of April 19, 1861, the Howard Dragoons helped keep the peace there, but most of the men refused to take the oath of allegiance to the United States. In May, armed with cavalry sabers and Colt's revolvers, they rode to Leesburg, Virginia, and joined the Confederate army, serving at different times as Company K, 1st Virginia Cavalry, Company M, 1st Maryland Cavalry, and Company K, 2nd Maryland Cavalry. Gaither was captured at Manassas Junction on August 27, 1862, later exchanged, and sailed to Europe the following year on a mission for the Confederate government. After the war, he became a cotton trader. Mason, William, and Joseph Shipley were enslaved at Oakland and neighboring farms when the Civil War began, and in 1863 they enlisted in the 9th U.S. Colored Troops. William Shipley was killed in Deep Bottom near Richmond, Virginia, in August 1864.