Illinois Colony, along with its cousins Ohio Colony and Iowa Colony, was a neighborhood settlement in extreme western Matagorda County just northwest of Palacios, which provided most services except for church and school. It was settled during the railroad promotions of the early 1900s and named after the home state of its inhabitants. Before about 1938 Illinois Colony had a one-room school that also hosted church services and community gatherings; in 1938 the building was moved to private property. County highway maps for the 1930s show a number of widely scattered farm units in the area northwest of Palacios where these neighborhood settlements were said to have stood. With the advent of improved transportation and school consolidation the settlements gradually disappeared. They are not labeled on 1952 maps.