Walgreen Company was founded in Chicago, Illinois, in 1901, and is headquartered in the Chicago suburb of Deerfield, Illinois. On December 31, 2014, Walgreens and Switzerland-based Alliance Boots merged to form a new holding company, Walgreens Boots Alliance Inc. Walgreens became a subsidiary of the new company, which retained its Deerfield headquarters and trades on the Nasdaq under the symbol WBA.

The company’s milestones:

1901 – Charles R. Walgreen Sr. purchased the Chicago drugstore where he had worked as a pharmacist – and that started the Walgreen chain. His energy and enthusiasm soon led to new ideas and ambitious expansion.

1909 – The second Walgreen store opened.

1916 – Nine stores incorporated as Walgreen Co.

1922 – Walgreens invented the malted milkshake. Customers stood three and four deep around the soda fountain to buy the “double-rich chocolate malted milk.”

1926 – The 100th store opened in Chicago.

1927 – Walgreen Co. stock went public.

1933 – Walgreens helped celebrate Chicago’s World Fair. The company opened four stores on the Century of Progress fairgrounds. These stores experimented with advanced fixture design, new lighting techniques and colors – ideas that helped modernize drugstore layout and design.

1943 – The company opened a nonprofit 6,000-foot drugstore in the Pentagon. All the profits from the store went to the Pentagon Post Restaurant Council, which supervised food service in the complex. The store operated into the 1980s.

1950 – Walgreens began to build self-service instead of clerk service stores in the Midwest. By 1953, Walgreens was the largest self-service retailer in the country.

1960 – Walgreens entered the Puerto Rico market.

1968 – Walgreens became the first major drug chain to put its prescriptions into child-resistant containers, long before it was required by law.

1975 – Walgreens reached $1 billion in sales.

1981 – The first Intercom computers were installed in five Walgreen pharmacies in Des Moines, Iowa. This was the initial step toward making Walgreens the first drugstore chain to connect all its pharmacy departments via satellite.

1982 – Next-day photofinishing became available chainwide.

1991 – In November, the chain completed installation of point-of-sale scanning to speed checkouts. Walgreens opened its first drugstore with a drive-thru pharmacy.

1994 – The 2,000th store opened in Cleveland.

1997 – Intercom Plus, Walgreens advanced computer system, completed rollout to all stores. Intercom Plus speeds the prescription-filling process, permits better patient counseling and is the leading pharmacy system in the industry.

1999 – Walgreens.com launched a comprehensive online pharmacy, offering customers a convenient and secure way to take care of many pharmaceutical and healthcare needs online.

2001 – Walgreens celebrated its centennial in June and rang the opening bell at the New York Stock Exchange.

2002 – Walgreens became the first drugstore chain to offer prescription labels in multiple languages chainwide.

2009 – Walgreens opened its first store in Alaska, marking its presence in all 50 states.

2011 –  Walgreens introduced Web Pickup service in the Chicago area, combining the convenience of online shopping with its neighborhood stores.

2014 – On December 31, Walgreens took its products and services to the four corners of the world with the completion of its merger with Alliance Boots, a leading international pharmacy-led health and beauty group.

According to walgreens.com; en.wikipedia.org.