St. Donatus is a city in Jackson County, Iowa, United States. The population was 135 at the 2010 census. St. Donatus is known for its status as a Luxembourger village, with historic architecture and views along U.S. Highway 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 Tetes des Morts, which is the name of a creek that flows through the village.