Rose Hill Manor, now known as Rose Hill Manor Park & Children's Museum, is a historic home located at Frederick, Frederick County, Maryland. It is a 2+1⁄2-story brick house. A notable feature is the large two-story pedimented portico supported by fluted Doric columns on the first floor and Ionic columns on the balustraded second floor. It was the retirement home of Thomas Johnson (1732–1819), the first elected governor of the State of Maryland and Associate Justice of the United States Supreme Court. It was built in the mid-1790s by his daughter and son-in-law.