St. Donatus is a city in Jackson County, Iowa, United States. The population was 120 at the time of the 2020 census. St. Donatus is known for its status as a Luxembourger village, with historic architecture and views along U.S. Route 52. It is the home of a historic Catholic church, which is dedicated to Saint Donatus of Muenstereifel, the town's namesake. It was formerly named Tete Des Morts, which is the name of a creek that flows through the village.

Jackson County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 19,485. The county seat is Maquoketa.