THE ONTARIO COUNTY LAND BRIEF
Land in the
Ontario Lowlands setting.
Ontario County has 644 square miles of land in New York. 2 mapped landscape regions meet across Ontario County: Ontario Lowlands, Finger Lakes Uplands and Gorges.
Glacially shaped lowlands and irregular plains border the Great Lakes and adjacent hills. The lakes influence regional weather, while local landforms reflect both glacial deposits and former shorelines.
Regional context: Eastern Great Lakes Lowlands ↗ · Regional mapping across the county footprint
Where the landscape changes
Ontario County intersects 2 mapped regional units. The largest mapped shares are:
- Ontario Lowlands66.8%
- Finger Lakes Uplands and Gorges33.2%
Northern Allegheny Plateau in Ontario County
Rolling hills, broad valleys and low mountains are mantled by glacial deposits. Sandstone, shale and siltstone underlie a mix of open land and woodland across the northern plateau.
Read the regional source ↗Finding your parcel within Ontario County
The atlas lists 31 cities, towns, townships, and Census communities associated with Ontario County, including Phelps, Canandaigua, Seneca. The list includes overlapping geography types and does not divide the county into exclusive service areas.
Ontario County by land and water
The Census records 18.5 square miles of water within Ontario County, or 2.8% of its total area. That share is close to Ontario County’s 2.8%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, Ontario County has 11.3 times the land area of nearby Canandaigua town (56.8 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Livingston County, Monroe County, Seneca County, Steuben County, Wayne County, Yates County within New York. A tract near one of these lines should be matched to the county identifier on its own records.

