Isaac Conroe was one of Montgomery County's most enduring sawmillers before 1900. His main offices and a sawmill were at Conroe but he operated mill locations at Egypt, about two miles to the southwest of the town; Haltom, location unknown; and his large sawmill at Beach, two miles east of Conroe, which he later sold to Trinity River Lumber Company.
I. Conroe's sawmill at Conroe appeared in an 1884 lumber directory. In 1893, he was reported to be cutting 15,000 feet daily.