Oneida County administrative offices are located at 800 Park Avenue, Utica NY 13501; phone: 315‑798‑5900.
Erected in March of 1798, the original county include the land that today comprises Lewis County, Jefferson County, and parts of Oswego County.
The area comprising Oneida County was not settled until after the Revolutionary War. Afterward, immigrants came into central and western New York in great numbers. The lands were effectively forfeited by the Iroquois Nation by virture of the fact that the Indians had been allied with the British. The Oneidas, part of the Iroqouis Nation, did not, howe ver, take up arms against American colonists. Utica Village, which would later become the Oneida County seat, grew out of a settlement that was made surrounding "Old Fort Schuyler."