A bur oak that took root circa 1499 in the Peoria region stood through the era when French explorers visited a land inhabited by Peoria Native Americans, was noted in early surveys by European settlers in the 1750s, and later stood on land acquired in the 1850s by Dr. and Mrs. E. H. Bradley. In the 1930s the Bradley family bought adjoining backlot property and had a large house razed so the tree's roots could grow unhampered. In the 1960s, descendants of the Bradley family, Peoria City Beautiful, and the Peoria Park District made possible the purchase of the property to save the oak. The Peoria Park District bought the site in 1971 and illuminated it, and in 1974 the site received the official name Giant Oak Park. In 1976, because it had lived during the American Revolutionary Period, the tree was designated a Bicentennial Tree by the International Society of Arboriculture and Nation Arborist Association, and from 1976 to 1977 “Frankie Acorn” Frank Hanbury, Jr. collected 200 acorns from it and planted them in four western states. In 1991 the Giant Oak Tree was designated Peoria's Tricentennial Tree in recognition of its 300 years of age, and a seed propagation project began through the Illinois Department of Conservation and the Peoria Urban Forestry Board. From 1992 to 1993, Peoria City Beautiful, the City of Peoria, and the Peoria Park District secured the eastward expansion of the tree's root system through a deed transferring land from private to public ownership, while the Peoria Park District owned and maintained Giant Oak Park. In 1994 the Giant Oak measured 50 feet high, had a spread of 110 feet, and a trunk diameter of 54.5 inches, and in 1995 it was marked as a historically and botanically significant tree by the Illinois State Organization National Society Daughters of the American Revolution.