Buffalo Grove is a village in Lake and Cook Counties in the U.S. state of Illinois. A suburb of Chicago, it lies about 30 miles (50 km) northwest of Downtown Chicago and 20 miles (32 km) north of O'Hare International Airport. As of the 2020 Census, Buffalo Grove has a population of 43,212. It totals 9.6 square miles (25 km2) of land, with the top three-quarters in Lake County and the bottom quarter in Cook County. Roads in the village such as Lake Cook Road and Illinois Route 83 converge on I-294. It is part of the Chicago Metropolitan Area.

Lake County is situated in the northeastern corner of the U.S. state of Illinois, along the shores of Lake Michigan. As of the 2020 census, it has a population of 714,342, making it the third-most populous county in Illinois. Its county seat is Waukegan, the tenth-largest city in Illinois. The county is primarily suburban, with some urban areas and some rural areas. Due to its location, immediately north of Cook County, Lake County is one of the collar counties of the Chicago metropolitan area. Its northern boundary is the Wisconsin state line.