New Kent County may have been named either for the English county of Kent or for Kent Island, in the upper waters of the Chesapeake Bay. William Claiborne, a native of Kent who had been driven from Kent Island by Lord Baltimore, was a prominent resident of the New Kent area about 1654 when the county was formed from York County. Part of James City County was added in 1767. The county seat is New Kent.

Records were destroyed when John Posey set fire to the courthouse on 15 July 1787. Many records were lost when the courthouse was partially destroyed by fire during Civil War hostilities in 1862. Additional records were burned in Richmond on 3 April 1865, where they had been moved for safekeeping during the Civil War.

An act passed in 1801 by the Virginia legislature required commissioners of the revenue annually to return a complete list of all free African Americans within their districts, with their names, sex, place of abode, and trades, and a copy of the list to be fixed at the courthouse door.