Sebastian is nine miles south of Raymondville on State highways 413 and 448 and the Missouri Pacific Railroad on the southern border of Willacy County. The community, settled before 1906, was first known as Stillman but was renamed Sebastian around 1912 in honor of John Sebastian, vice president of the Rock Island Railroad Company, which helped to develop the area. In 1914 Sebastian had a population estimated at ninety, one grocer, one cattle breeder, and two general stores. In 1925 the community had a population of seventy-five; by 1927 it had 200 residents. In 1931 Sebastian had eighteen businesses, a post office, and an estimated population of 300. A railroad stop, various dwellings, a tourist camp, fifteen businesses, two churches, and seasonal industries were in Sebastian in 1948, when the estimated population was 400. In 1953 the population had increased to 500 and businesses to twenty-two. In 1969 Sebastian reported a population of 404 and thirteen businesses, and in 1990 the population was 1,598 but only seven businesses were listed. The 2000 census reported a population of 1,864 with fourteen businesses.