This was long the territory of the Oneida people, one of the first Five Nations of the Iroquois Confederacy or Haudenosaunee.

They occupied the area until after the Revolutionary War, when they were forced off the land, although they had been allies of the patriot colonists.

However, territories located to the west of present-day Pennsylvania were under effective French control as part of New France.

The county was named for William Tryon, the British colonial governor of New York.

In the years prior to 1776, during the increasing tensions most of the Loyalists in Tryon County fled to Fort Niagara on the Western Frontier.

In 1788, the Oneida Reservation was considerably reduced by what is known as Clinton's Purchase, when land was sold off west of the Unadilla River to create what are now 20 towns.

Settlers from eastern New York and New England entered the area and began farming.

The land had been purchased the previous year from the Oneida, who were forced into a smaller reservation to the north.

This established the current borders of Chenango County, which have been maintained to the early 21st century.

[4] Chenango County is in the approximate center of the state, located west of Albany, north of Binghamton, and southeast of Syracuse.

In 2006 both Eliot Spitzer and Hillary Clinton carried it, winning 57% and 54% of the vote for governor and US Senator, respectively.

In 2008, John McCain carried Chenango County over Barack Obama in the presidential election by a close margin of 49.59%-48.45% or a difference of 237 votes.

In addition to the city of Norwich, the county has the following named settlements: In New York, a "town" is a political subdivision (synonymous with township).

The towns in northern Chenango County originated from the Twenty Townships ceded by the Oneida tribe to the State of New York.