The Niagara Frontier refers to the stretch of land south of Lake Ontario and Lake Erie and extending westward to Cleveland, Ohio. The term dates to the War of 1812. This only includes the land east of the Niagara River and south of Lake Erie within the United States. The western side of the Niagara River on the Canadian/Ontario side is the Niagara Peninsula and is considered part of the Golden Horseshoe.
The Niagara Frontier is most commonly referred to as the land bordering the eastern Niagara River and southern shores of Lake Erie and Lake Ontario and is part of the region known as Western New York State. The Niagara Frontier also forms the eastern part of the Great Lakes North Coast, while its southeastern boundary forms what is known as ski country.
- Erie County, New York north of US 20A - includes Buffalo, New York
- Niagara County, New York - includes Niagara Falls, New York
- Orleans County, New York
- Genesee County, New York - includes Batavia, New York
Other, less common, definitions may also include the following areas:
- Erie County, NY south of US 20A (also known as the Buffalo Southtowns)
- Chautauqua County, New York (particularly the area that is part of the Lake Erie watershed, north and west of the Chautauqua Ridge. This is in contrast to the southeastern part of the county, in the Conewango Creek watershed, which is NOT part of the Niagara Frontier and is instead part of the adjacent Southern Tier to the east)
- Erie County, Pennsylvania - includes Erie, Pennsylvania
- Ashtabula County, Ohio
- Lake County, Ohio
- Cuyahoga County, Ohio - includes Cleveland, Ohio