In 1845 Isaac settled near Round Top in Fayette County, where he became a prosperous planter and slave owner and represented that county in the Senate of the Fifth and Sixth legislatures (1853-57). In 1863 Hill paid an unknown substitute to serve in his place in Capt. Zebulon M. P. Rabb's company of the Plum Grove Rifles, a Home Guard unit. He later served as a private in Capt. James C. Gaither's company, the Round Top Guerrillas, organized by Brig. Gen. William G. Webb as a volunteer cavalry "to repel armed or hostile invasions of the state." Hill was married three times and had nine children. During the 1870s he was a promoter and stockholder of the Central railroad. He died at his home on July 18, 1889, and was buried near Round Top.
30° 06.523, -096° 41.512