Hadley (/ˈhædliː/ ⓘ, HAD-lee)[4] is a town in Saratoga County, New York, United States.

The Town of Hadley is in the northern part of the county and is west of Glens Falls.

In 1930, the Conklingville Dam by the west town line helped create the Sacandaga Reservoir and controlled flooding.

The northern and eastern town lines are the border of Warren County.

New York State Route 9N passes through the southeastern part of Hadley.

19.3% of all households were made up of individuals, and 7.8% had someone living alone who was 65 years of age or older.