Effingham is the largest city in, and the county seat of, Effingham County, Illinois, United States. The population was 12,604 at the 2015 census estimate. Effingham is part of the Effingham, IL Micropolitan Statistical Area.The city bills itself as "The Crossroads of Opportunity" because of its location at the intersection of two major Interstate highways: I-57 running from Chicago to Miner, Missouri, and I-70 running from Utah to Maryland. It is also served by U.S. Route 45, which runs from Ontonagon, Michigan to Mobile, Alabama, U.S. Route 40, the historic National Road, which stretches from Atlantic City, New Jersey to Summit, Utah, and Illinois routes 32 and 33 also run through the city. It is also a major railroad junction, the crossing of the Illinois Central main line from Chicago to Memphis with the Pennsylvania Railroad line from Indianapolis to St. Louis. Thus, Effingham has a broad range of restaurants, and lodging facilities.