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.

Clayton County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 17,043. Its county seat is Elkader. The county was established in 1837 and was named in honor of John M. Clayton, United States Senator from Delaware and later Secretary of State under President Zachary Taylor.