Mundelein, village, Lake county, northeastern Illinois, U.S. A suburb of Chicago, it lies 35 miles (55 km) north-northwest of downtown. Before settlement the area was inhabited by Potawatomi Indians. The village was founded in 1835 and was successively known as Mechanics Grove, for the English tradesmen who immigrated to the area; Holcomb (1850), for a wealthy local leader; Rockefeller, for industrialist John D. Rockefeller; and Area, based on the acronym (for “Ability, Reliability, Endurance, and Action”) coined by educator Arthur Sheldon for a sales school he established in the village. In 1924 it was renamed in honour of George Mundelein, archbishop of Chicago (1915–39), who helped to establish in the village St. Mary of the Lake Seminary (opened in 1921; now the University of St. Mary of the Lake/Mundelein Seminary); in 1926 the seminary hosted the International Eucharistic Congress, which brought hundreds of thousands of visitors. Mundelein is mainly residential but has some industry, including telecommunications and the manufacture of medical supplies, packaging, and metal fasteners. Inc. 1909. Pop. (2000) 30,935; (2010) 31,064.