Southdown Plantation was more than a grand mansion; with its own railroad system, refinery, sugar house, and company store, it was once a small town in itself and an enterprise that formed the root of Houma's sugar industry. W.J. Minor built the first sugar mill here in 1846, one of 86 mills that operated in Terrebonne Parish during the industry's boom years. Molasses, a by-product of sugar refining, was used to make rum, and plantation managers paid workers in scrip or tokens redeemable at the company store. Before and after the Civil War, Southdown laborers lived on site in workers cabins, while the plantation's operations included an overseer's house, a storage warehouse, a mill yard crane hoist, and sugarcane fields. The plantation owned 16 locomotives with 26 miles of track, including a railroad bridge where tracks crossed the bayou, and it also owned 26 barges, towed by steamboats, that picked up cane grown along the bayous. Southdown once incorporated 8,000 acres of cane fields, and during the grinding season the mill operated 24 hours a day while the refinery could produce as much as 40 million pounds of granulated sugar in a year. Using bricks fired here, W.J. Minor built the first floor of the Greek-Revival mansion about 1858-1859, and in 1893 Henry Minor built the mansion's second floor and added stained glass panels featuring sugarcane leaves. Pecan trees provided shade and nuts for making pralines, managers hired women to keep the refinery running during World War II, and sugarcane operations ended here in 1975.