Question: Which Maine county had a 2010 population of over 50,000 and was where the designer of the Eaton School began his career?
Sentence (from "Eaton School (Norridgewock, Maine)"): Originally built in 1866-67 to house a private academy and the local Masonic lodge, it is notable as an early design of Charles F. Douglas, a Maine native whose career began in Somerset County.
Relevant evidence: Yes