The land was acquired by Joseph Medill as a country estate, which he called Red Oaks, in the late 1800s. After his death, the estate passed to his grandson, Colonel McCormick. Colonel McCormick served in World War I and saw action at the Battle of Cantigny. After returning home, he renamed the estate in honor of the battle.
Colonel McCormick had no children. When he died in 1955, he left his fortune to establish the McCormick Charitable Trust (now the McCormick Foundation). He also directed that Cantigny should be transformed into a park for the use of the general public. Since then, the McCormick Foundation has used the endowment funds bequeathed by Colonel McCormick to operate Cantigny as a public facility.
In 1896–1897, Joseph Medill built a 35-room mansion on the estate; it was designed by architect Charles Allerton Coolidge. Today the mansion is the Robert R. McCormick Museum, a historic house museum which is open to the public for tours.
During World War I, Colonel McCormick served with the First Division of the United States Army—also known as the "Big Red One". Colonel McCormick provided an endowment for the First Division Museum, which was designed by architect Andrew Rebori. The museum has exhibits and artifacts chronicling the First Division's service history, not only in World War I, but also in World War II and later U.S. wars.
On display outside the museum is the area's largest collection of tanks and artillery pieces, known as "Tank Park". The collection includes tanks and armored vehicles from the First World War up to the present day. Visitors are allowed to climb on the vehicles.