[3] The name is in honor of Joseph C. Yates, who as Governor of New York signed the act establishing the county.

Yates County is included in the Rochester, NY Metropolitan Statistical Area.

In 1784, following the peace treaty that ended the American Revolutionary War, the name of Tryon County was changed to honor the general, Richard Montgomery, who had captured several places in Canada and died attempting to capture the city of Quebec, replacing the name of the hated British governor.

On February 5, 1823, Yates County was formed from 310 square miles (800 km2) of Ontario County, including the area that included Vine Valley, Middlesex, Penn Yan, and Dresden, New York.

[4] On January 1, 1826, 60 square miles (160 km2) of Steuben County was partitioned and added to Yates, which included Starkey, Dundee, and Lakemont, New York.

[5] On April 15, 1828, 10 square miles (26 km2) was partitioned from Yates, and passed to Seneca and Tompkins counties, mostly in the forest.

[6] On March 17, 1860, Ontario County was authorized to gain land from Yates, but it was never put into effect.

It grew quickly and steadily and with a population of more than 3,000 in 2015 it was almost as large as the Lancaster County, Pennsylvania settlement.

[10] Yates County is in the western part of New York State, northwest of Ithaca and southeast of Rochester.

21.3% were of English, 16.5% German, 11.4% Irish, 10.7% American, 5.3% Danish and 5.3% Italian ancestry according to Census 2000.

[21] The county's Highway Department is headquartered in Penn Yan and is charged with maintaining roads, including:[22] Each town and village within Yates County maintains its own highway department.