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. Before European colonization, Native American Potawatomi tribes inhabited the present area. The name "Buffalo Grove" comes from the English translation of the Potawatomi name for Buffalo Creek, which flows through some of the village. Initial Homesteaders sold their land to agricultural Catholic German immigrants, who established St. Mary's Church and a school. The area remained small and rural and character until housing developers began building single-family houses after the Korean War. After being incorporated in 1958, Buffalo Grove experienced a population boom for the rest of the 20th century. The village hosted a 50th Anniversary Celebration in 2008. The village features dozens of recreational facilities, parks, and festivals, including a months-long Farmers' market, two golf courses, and the popular "Buffalo Grove Days". Buffalo Grove has an elected council-manager government with home rule status. The local government's public works department is nationally accredited. Economically, residents work in health care, education, and professional services, while businesses in the village employ 20,000 daytime workers in 10 million square feet of commercial and industrial space.