Mentor is a city in Lake County, Ohio, United States. Mentor was first settled in 1797. The population was 47,159 at the 2010 census. In July 2010, CNNMoney.com ranked Mentor 37th in a list of the Top 100 Best Places to Live in America. In 1876 James A. Garfield purchased a home in Mentor, from which he conducted the first successful front porch campaign for the presidency. Garfield coined the term "Mentorite" when referring to a native of Mentor. That house is now maintained as the James A.