The Isaac Heffron House is a two-story building located at 1509 Postoffice Street (Avenue E) in the East End Historic District of Galveston, Texas. The house was built by Isaac Heffron, a prominent Galveston contractor in the Victorian period and during the city's recovery from the 1900 Galveston Hurricane. Later, the house was the residence of T.J. Holbrook, a Texas state senator from 1922 to 1939.