Rock Island, on U.S. Highway 90A fifteen miles west of Eagle Lake and twelve miles southwest of Columbus in southwest Colorado County, was settled in 1896 as part of a land promotion scheme on the Texas and New Orleans Railroad. Among the first residents of the community were Abram Vorhees, Charles Petersen, and C. S. Penfield. The town's original name was Crasco, after nearby Crasco Creek, but in 1897 the citizens successfully petitioned the post office department to change the name. Charles Petersen, a large landowner, renamed the town for the Rock Island Railroad Company. In August 1897 Petersen was appointed the first postmaster of Rock Island, and the old Crasco post office was closed. From an original core of thirty-nine farming families, the population of Rock Island had grown to 367 by 1904 and had reached an all-time high of 500 by 1925. By 1986 the population had dropped to 160, and only eight businesses remained. In 2000 the population remained at 160, and there were five businesses in the community.