New York's 23rd congressional district is located in Upstate New York, and covers part of Buffalo's Northtowns, all of the Southtowns, and much of the Southern Tier. The district includes two of the eleven Finger Lakes: Keuka Lake and Seneca Lake.

The Southern Tier is a geographic subregion of the broader Upstate region of New York State, geographically situated along or very near the state border with Pennsylvania. Definitions of the region vary widely, but generally encompass counties surrounding the Binghamton and Elmira-Corning metropolitan areas. This region is adjacent to the Northern Tier of Pennsylvania, and both these regions together are known as the Twin Tiers.