Herkimer County Administrative Offices are located at 109 Mary Street, Herkimer NY 13350; phone: 315‑867‑1002.
Herkimer County was formed from Montgomery County, February 16, 1791. The name was originally Erghemar, and it has been variously written as Herchkeimer, Hareniger, Herchamer, Harchamer, Harkemar, and Herkimer. Onondaga was taken off in 1794; Oneida and part of Chenango in 1798; parts of Montgomery were annexed in 1817.
The county is approximately 80 miles from Albany and contains [in 1860] 1,745 square miles. The Mohawk River flows through the county in a deep valley which cuts the ridges at right angles and separates the highland into 2 distinct parts.
The county seat is located in the village of Herkimer. The Erie Canal crosses the county.
The first settlements were upon the river intervales, above Little Falls, by a colony of Palantine Germans. Accessions were made to their number from time to time, and close to the Revolution they constituted almost the sole inhabitants of the county. During the French War of 1756, this colony was twice invaded and numbers of people were killed or taken away as prisoners. It was also repeatedly invaded during the Revolution; buildings were destroyed; and at last the inhabitants were obliged to abandon their homes and seek protection in the lower part of the valley.
After the war settlements spread rapidly, and within 15 years over 10,000 people for New England and the eastern New York counties, locating in the central and southern portions.