Alpha is a village in Henry County, Illinois, United States. The population was 671 at the 2010 census, down from 726 at the 2000 census.
On June 1, 1872, Anson Calkins laid out the village of Alpha. Alpha was created as a railroad town and replaced the town of Oxford, which was located about three miles west of current day Alpha. The village was named Alpha (the first letter of the Greek alphabet), because Calkins believed it to be the beginnings of a great city. It was incorporated on January 11, 1895. In the early 1980s, director Barry Levinson looked at Alpha's railroad car diner as a possible location for filming scenes for his movie Diner. Alpha's zip code (61413) is Pi in reverse (3.1416).