Katherine Louisa Keith (nee: West) was born in Toronto in 1912. She was the great-granddaughter of Robert West and became his last living descendant.The Robert West House fell into disrepair in the 30's and early 40's. In 1945, Mrs Keith decided to make it liveable again. In 1946, she started residing there in the Summertime. In 1949, she made it her full-time residence.In 2008, with her advancing age, she decided that the best way to ensure that the house was preserved was to donate it to an appropriate organization. As a result, the Thornhill Heritage Foundation was formed. In July 2009, the transfer of the house and the property to the new Foundation was completed. Mrs. Keith continued to live in the house until her death in April 2011.