Schoharie County (/skoʊˈhɛəriː/ skoh-HAIR-ee) is a county in the U.S. state of New York. As of the 2020 census, the population was 29,714, making it the state's fifth-least populous county. The county seat is Schoharie. "Schoharie" comes from a Mohawk word meaning "floating driftwood." Schoharie County is part of the Albany-Schenectady-Troy, NY Metropolitan Statistical Area and thus the Capital District of New York. The county is part of the Mohawk Valley region of the state.

The large territory of the county was long occupied by the Mohawk Nation and, to the west, the other four tribes of the Iroquois (Haudenosaunee) Confederacy (increased to six with the migration of the Tuscarora). After European colonization of the Northeast started, the Mohawk had a lucrative fur trade with the French coming down from Canada, as well as the early Dutch colonists, and later British and German colonists.

Some Palatine Germans, who worked in camps on the Hudson to pay off their passage in 1710, later settled in this county in the 1720s and 30s. In addition, Scots-Irish immigrants settled in the present Schoharie County area before the American Revolutionary War, especially near Cherry Creek.

After Great Britain defeated the Dutch in the Second Anglo-Dutch War and received New Netherland via the Treaty of Breda, they began to establish counties in the New York territory in 1683. The present Schoharie County was first part of Albany County. In theory, it extended westward to the Pacific Ocean, as the colonists wanted to keep their options open. This county was reduced in size on July 3, 1766, by the creation of Cumberland County, and further on March 16, 1770, by the creation of Gloucester County, both containing territory now part of Vermont.

On March 12, 1772, what was left of Albany County was split into three parts, one retaining the name Albany County. Tryon County was formed from the western portion of the territory (and thus, since no western boundary was specified, theoretically still extended west to the Pacific). The eastern boundary of Tryon County was approximately five miles west of the present city of Schenectady, and the county included the western part of the Adirondack Mountains and the area west of the West Branch of the Delaware River. The area then designated Tryon County was eventually organized into what are now 37 counties of New York State. The county was named for William Tryon, colonial governor of New York.

In the years preceding 1776, as social and political tensions rose in the colony, most of the Loyalists in Tryon County, then on the frontier, fled to Canada. In 1784, after the peace treaty that ended the Revolutionary War and the establishment of states, the new government changed Tryon County's name to Montgomery County to honor United States General Richard Montgomery, who had captured several places in Canada and died trying to take the city of Quebec.

The state continued to organize new counties. In 1789, Montgomery County was reduced in size by the splitting off of Ontario County. It was originally much larger than the present county, including present-day Allegany, Cattaraugus, Chautauqua, Erie, Genesee, Livingston, Monroe, Niagara, Orleans, Steuben, Wyoming, Yates, and part of Schuyler and Wayne counties.

In 1791, Otsego, Herkimer and Tioga Counties were split off from Montgomery.