The Walgreen Company (Walgreens, or sometimes archaically Walgreen) is the largest drug retailing chain in the United States. As of May 31, 2014, the company operated 8,217 stores in all 50 states, the District of Columbia, Puerto Rico and the U.S. Virgin Islands. It was founded in Chicago, Illinois, in 1901. The Walgreens headquarters office is in the Chicago suburb of Deerfield, Illinois.