Marquette is a city in Clayton County, Iowa, United States. The population was 429 at the time of the 2020 census, up from 421 in 2000. The city, which is located on the Mississippi River, is named after Jesuit missionary Jacques Marquette, who along with Louis Joliet discovered the Mississippi River just southeast of the city on June 17, 1673.

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.