Mentor ( MEN-tər) is the largest city in Lake County, Ohio, United States. The population was 47,450 at the 2020 census. It is part of the Cleveland metropolitan area. Mentor was first settled in 1797. In 1876, James A. Garfield purchased a home in Mentor, from which he conducted the first successful front porch campaign for the presidency; the house is now maintained as the James A. Garfield National Historic Site. The city is home to Headlands Beach State Park, the longest public swimming beach in Ohio. The city is a major center of retail stores and restaurants. Mentor Avenue (US 20) is the city's commercial corridor, which includes Great Lakes Mall, and additional shopping is found along most major roads. Manufacturing in the city includes medical products, polymers, plastics, electric boards, and other peripherals that generally serve the computer and automation industries. Convenient Food Mart and medical equipment company Steris are based in Mentor. CSX Transportation and Norfolk Southern railroads both pass through the city.