Returning to the U.S., MacArthur took command of the IV Corps Area, based at Fort McPherson in Atlanta, Georgia, on 2 May 1925. However, he encountered southern prejudice because he was the son of a Union Army officer, and requested to be relieved. A few months later, he assumed command of the III Corps area, based at Fort McHenry in Baltimore, Maryland, which allowed MacArthur and Louise to move to her Rainbow Hill estate near Garrison, Maryland. However, this relocation also led to what he later described as "one of the most distasteful orders I ever received": a direction to serve on the court-martial of Brigadier General Billy Mitchell. MacArthur was the youngest of the thirteen judges, none of whom had aviation experience. Three of them, including Summerall, the president of the court, were removed when defense challenges revealed bias against Mitchell. Despite MacArthur's claim that he had voted to acquit, Mitchell was found guilty as charged and convicted. MacArthur felt "that a senior officer should not be silenced for being at variance with his superiors in rank and with accepted doctrine".