Clarence is a city in Cedar County, Iowa, United States. The population was 1,039 at the time of the 2020 census. The community was origin…Clarence is a city in Cedar County, Iowa, United States. The population was 1,039 at the time of the 2020 census. The community was originally called "Onion Grove" because of the widespread growth of wild onions along Mill Creek. The village was moved in order to be close to a railroad line and the name was changed to "Clarence" on the suggestion of Clarence, New York native Richard Gere.