The Southern Lumberman's Directory of American Saw Mills and Planing Mills, 5th edition lists an H. C. Calfee operating a sawmill at Conroe in 1928. The mill was located near Leonidas, about five miles west of Conroe. Calfee either purchased or built a sawmill there in 1925. In May, 1927, Calfee manufactured more than 77,000 feet of lumber for two customers, the Foster-Buhmann Lumber Company and the First National Bank of Conroe. The mill have been closed during the Great Depression and World War II.
H. C. Calfee sold the mill and site to Roy L. Willis Lumber Company for $10 on June 28, 1948. The sale of 1948 included assets of the sawmill, a 1944 truck, a 1947 truck, one trailer, two mules and a wagon, one rubber-tired wagon, saws, axes, two 55-horsepower International power plants, one 4-inch feed, two edgers, a mandrel, a carriage and track, a gas motor, a chain and slab conveyor, a dust blower, and a sawmill shed. Willis later moved it to Highway 75 North.
By 1963, the company was making pulpwood chips with a debarker, a 3-knife chipper, and a chip screen. In 1973, Roy L. Willis Lumber Company produced four million feet of lumber. In 1975, Roy L. Willis retired and advertised his machinery for sale. The ad noted he had an all-electric sawmill that cut 600,000 board feet per month, which could be easily expanded, concrete and steel buildings, a 26-inch Cambio debarker, chippers, conveyors, a 28-separator sorter, a dry kiln, a planing mill, and storage shed, all located on twenty-four acres.