The Ringling brothers were five American siblings who transformed their small touring company of performers into one of the largest circuses in the United States during the late 19th and early 20th centuries. Four brothers were born in McGregor, Iowa: Alfred T., Charles, John and Henry William, and the family lived in McGregor for twelve years, from 1860 until 1872. The Ringling family then moved to Prairie du Chien, Wisconsin, and finally settled in Baraboo, Wisconsin, in 1875. They were of German and French descent, the children of harness maker Heinrich Friedrich August Ringling (1826–1898) of Hanover, and Marie Salome Juliar (1833–1907) of Ostheim, in Alsace. While there were seven Ringling brothers, Alfred, Charles, John, Al and Otto Ringling were the main brothers in charge of the circus shows. All of the brothers were Freemasons. In 1919, they merged their Ringling Brothers Circus with America's other leading circus troupe, Barnum and Bailey, ultimately creating the Ringling Bros. and Barnum & Bailey Circus, which has operated continuously since except for a hiatus from 2017 to 2022.

McGregor is a city in Clayton County, Iowa, United States. The population was 742 at the time of the 2020 census. McGregor is located on the Mississippi River across from Prairie du Chien, Wisconsin. Pike's Peak State Park is located just south of the city. Just to the north of McGregor is the city of Marquette. The community of McGregor Heights lies in the southern parts of the city limits.