The city of Mahopac encompasses the following counties: Putnam.

Mahopac encompasses land area: 5.3 sq mi (13.7 km2), water area: 1.1 sq mi (2.9 km2). The elevation is 666 ft (203 m) above sea level. This equates to a population density of 1,579/sq mi (610.8/km2). The local time zone is Eastern (EST) (UTC-5).

Local area codes are 845. The Federal Information Processing Standard (FIPS) code for the city is 36-44534, which is used in computer filings when non-government agencies and contractors fulfill government contracts.

Short Description
Mahopac, New York, is a hamlet (and census-designated place) in the Town of Carmel in Putnam County, New York. An exurb of New York City some 47 miles (76 km) to the south, Mahopac is located on US Route 6 on the County's southern central border with Westchester County. As of the 2011 census, the population was 8,675.

Mahopac and Mahopac Falls play central roles in the history of Putnam County.

Originally inhabited by the Wappinger Native Americans, an Algonquian tribe, the hamlet's land was patented in 1697 by Adolphus Philipse, son of a wealthy Anglo-Dutch gentryman. During the French and Indian War, Wappingers throughout Putnam County traveled north to Massachusetts to fight for the British.