In 1946, Harry Watson purchased the Mill from Mrs. Spratt, changing the Mill’s name to “Watson’s Mill” as one of his first acts as owner. A sign was erected on the front of the Mill, where it has remained ever since. He decided that the lawn in front of the Dickinson house would not be built upon and Mrs. Spratt continued to live the home. In 1948, Harry purchased the Dickinson House.
In 1963, the National Capital Commission entered into a lease agreement with Watson, hoping to open the Mill as a heritage attraction. In the 1970s, the Rideau Valley Conservation Authority purchased the Mill, taking on many essential restoration projects which allowed a museum to be built and celebrated.