The Walgreen Company (Walgreens) is the largest drug retailing chain in the United States. As of January 31, 2014, the company operated 8,678 stores in all 50 states, the District of Columbia, Puerto Rico, the U.S. Virgin Islands and Guam. It was founded in Chicago, Illinois, in 1901. Walgreens headquarters are in the Chicago suburb of Deerfield, Illinois.