At 68 years of age at the time of his inauguration, Harrison was the oldest person to assume the U.S. presidency, a distinction he held until 1981, when Ronald Reagan was inaugurated at age 69. Due to his brief tenure, scholars and historians often forgo listing him in historical presidential rankings. However, historian William W. Freehling calls him "the most dominant figure in the evolution of the Northwest territories into the Upper Midwest today".