Tioga County is a county located in the U.S. state of New York. As of the 2010 census, the population was 51,125. Its name derives from an American Indian word meaning "at the forks," describing a meeting place. Its county seat is Owego.
In 1789, Montgomery County was reduced in size by the splitting off of Ontario County. The actual area split off from Montgomery County was much larger than the present county, also including the present Allegany, Cattaraugus, Chautauqua, Erie, Genesee, Livingston, Monroe, Niagara, Orleans, Steuben, Wyoming, Yates, and part of Schuyler and Wayne counties.
Tioga County was one of three counties split off from Montgomery County (the others being Herkimer and Otsego Counties) in 1791. Tioga County was at this time much larger than the present county, also including the present Broome and Chemung counties and parts of Chenango and Schuyler counties.
Tioga County was reduced in size in 1798 by the splitting off of Chemung County (which also included part of the present Schuyler County and by the combination of a portion with a portion of Herkimer County to create Chenango County. In 1806 it was further reduced by the splitting off of Broome County.