Cook County, Illinois, is the second-most populous county in the United States, home to over 5 million residents. It encompasses the city of Chicago, which is the county seat and the third-largest city in the country. The county is known for its diverse communities, rich history, and vibrant culture. Cook County covers approximately 946 square miles and includes numerous suburbs and unincorporated areas. It features a variety of parks, recreational facilities, and cultural institutions, such as the Art Institute of Chicago and the Field Museum. The county plays a significant role in the economy and governance of the region.