South Bristol is the smallest town in Ontario County. While there have been some fluctuations, the Town's population has remained relatively stable for most of its history. The census of 1840 showed a population of 1375, while the most recent census of 1990 reported a population of 1663 - an increase of just over 20% in 150 years.

The town of South Bristol is characterized by four high ridges ranging north and south and rising 500 feet to well over 1000 feet above the intervening valleys.

Approximately one-third of the Town is located within the Canandaigua Lake watershed, with the remaining areas draining to Mud Creek and Honeoye Lake. Grimes and Mud Creeks run through the valleys, as well as a number of smaller streams, many of which have carved deep gullies descending from their highland sources. Large wetlands are found in the southwestern part of Town, as well as many smaller ones through the town.

With few exceptions, the Town is mostly agricultural, forestland, and residential in character. Residential uses are most heavily concentrated along State Routes 64 and 21, County Roads 12 and 34, and along the lakeshore. The rest of the Town is sparsely populated, and either undeveloped forest or agricultural lands

Recreational areas include a ski resort, a golf course, a large New York State owned recreation area, the Ontario County Park, a scout reservation, and the Rochester Museum's Cumming Nature Center, which together occupy large tracts. The State maintains a public boat launching area adjacent to and within the Town's southern boundary.