Brunswick County was named for the duchy of Brunswick-Luneburg, one of the German possessions of King George I. It was formed by statute in 1720 from Prince George County and on 31 October 1723 the boundaries of the county were ordered to be laid out, but, because of the sparse population, the county court first met in June 1732. Brunswick County was enlarged by the addition of parts of Surry and Isle of Wight Counties in 1733. The county seat is Lawrenceville.

An Act to stay the collection of debts for a limited period, or Stay Law, was passed by the General Assembly of Virginia on March 2, 1866. It was passed in response to the loss and destruction of property during the Civil War. A large proportion of people's wealth was greatly diminished during the war making it difficult to repay creditors. The Stay Law halted all court proceedings that involved the collection of debt. The General Assembly made an exception for minors, widows, unmarried women, and insane persons whose support was dependendant on the interest on or or principal of any debt. They had to petition a commissioner in chancery who would examine their case and present his report to the local court for approval.