John “Jack” Elwood McGregor came from a farming family in Nova Scotia, Canada, and followed his parents to California in 1893, after they had moved to Highland. Jack and his brother, James, worked in the mines in Indio and by 1902, Jack had become a tinsmith and was living at the Hayt Hotel on Main Street in Riverside.
McGregor and Henry W. Fletcher opened the Glenwood Saddle Livery at 650 Market Street in 1906 and Jack purchased other Riverside County properties, including the Iron Chief Mines at Eagle Mountain, which he later sold to Kaiser Steel. He also conducted large scale farming operations in the Ethanac area.
His civic-mindedness and interest in agriculture led McGregor to participate in establishing the Riverside County Fair, later known as the Southern California Fair, on fairgrounds near Fairmount Park. Fairground Street near Market Street and Fairmount Boulevard commemorates the site. The fairgrounds included a racetrack and the fair featured aerial stunts by “Cowboy Aviator,” Roman Warren. In 1926, Warren famously flew his plane under the Mission Bridge.
Jack McGregor was elected county supervisor for the third district in 1924, reelected twice, and then made chairman in 1935. In 1934, he was elected president of the County Supervisors Association of California. McGregor died in office in 1936, survived by his wife Jane (Singletary) McGregor.