Mundelein is a village in Lake County, Illinois, in the United States. As of the 2010 census, the village population was 31,064.
The community now known as Mundelein has been inhabited since at least 1650, when the Potowatami Indians were known to have been trading with French fur traders. The first European inhabitants reached the area in the early 19th century. Peter Shaddle (for whom a street is named) was the first known settler, building a log cabin in the area now owned by St. Mary of the Lake Seminary in 1835.
The next settlers were tradesmen escaping from England's industrial depression, who became farmers in the Mundelein area. In honor of their former professions, they named the city "Mechanics Grove", and built schools, churches, and businesses. The community grew and (while still unincorporated) changed its name to "Holcomb" in honor of John Holcomb, a person who was active in the area's development. As Holcomb, the community added a railway station and a post office. The Holcomb area incorporated in February 1909 under a new name, "Rockefeller"; a reference to businessman John D. Rockefeller.