According to the United States Census Bureau, the town has a total area of 56.0 square miles (145.1 km²), of which, 55.8 square miles (144.6 km²) of it is land and 0.2 square miles (0.5 km²) of it (0.36%) is water. Farmington is drained by Wilson Stream, Temple Stream, Beaver Brook and the Sandy River.

The town is crossed by U.S. Route 2 and Maine State Route 4, Maine State Route 27, Maine State Route 43,Maine State Route 133, and Maine State Route 149.It borders the towns of Industry and New Sharon to the east, Chesterville to the south, Wilton to the southwest, Temple to the west, and Strong and New Vineyard to the north.

Farmington has four areas that it is locally divided up into, and is also sometimes mapped in that way. These areas are West Farmington, Fairbanks, Farmington Falls, and Farmington (downtown). All except Fairbanks have their own zip code, but they are all still within Farmington.

• Town of Farmington, ME - 153 Farmington Falls Road Farmington, Maine 04938
  phone:207-778-6538 Fax:207-778-5871
• Farmington Public Library - 117 Academy Street,Farmington,maine 04938
  Phone: 260-726-7890 Fax:260-726-7317