Hanover County was formed in 1720 from New Kent County.

An Act of Assembly from 15 February 1900 established the procedures by which African American minors could be committed to the negro reformatory and the procedures for receiving compensation from the commonwealth. Compensation for care costs was received by submitting accounts to the Hanover county judge and was paid in the same amounts as jailors for prisoners in jail.

The Virginia Manual Labor School, sometimes called the Virginia Manual Labor School for Colored Boys, was established in 1897 by John Henry Smyth in Hanover County, Virginia, to where African American youths who were arrested were sent, instead of Virginia's penal institutions. African American minors sentenced to the school were sent there to be rehabilitated. In the process, they learned a trade. Smyth served as president until his death 5 September 1908.

Most county court records, particularly deeds, wills, and marriage records, were destroyed by fire in Richmond on 3 April 1865, where they had been moved for safekeeping during the Civil War. The circuit court records were not moved to Richmond and were relatively unscathed. Consequently, there is a strong run of common law papers and chancery papers after 1831 that were generated by the circuit superior court of law and chancery and its successor, the circuit court.