In 1850, Edward McCormick was in his first few years of managing Clermont, his farm with 407 improved acres, with the labor of 23 enslaved people he owned. He had been orphaned at 12, was sent to Princeton by his uncle and guardian Dr. Cyrus McCormick, graduated in 1845, and inherited Clermont. He was married to his first wife, Mary Elizabeth Stribling McCormick (who would die just three years later), had a daughter, Florinda, and an infant daughter, Mary Elizabeth, who died that year, 1850.  They lived in the 1755-56 house and its adjacent parts. 

In 1948, about 100 years after Edward McCormick started farming, Gilbert L. Royston was retiring from the farming business, having operated Clermont since 1939 on a 50-50 share basis with its owners, the grandchildren of Edward McCormick through his son, Admiral A.M.D. McCormick. The Royston family lived in the tenant house (ca. 1917) overlooking the farm, opposite the bank barn of the same year.