Sealy is a city in Austin County, Texas within the HoustonSugar LandBaytown metropolitan area. The population was 5,248 at the 2000 census. Sealy is located 50 miles west of the downtown Houston area. According to the United States Census Bureau, the city has a total area of 6.9 square miles (18Square kilometers), of which, 6.9 square miles (18Square kilometers) of it is land and 0.04 square miles (0.10Square kilometer) of it (0.29%) is water. San Felipe, Texas sold part of its original 22,000 acre township to Gulf, Colorado, and Santa Fe Railroad to create Sealy in 1879. In 1881, Daniel Haynes, a cotton gin builder, filled a request for a cotton-filled mattress which started a company.