Many slaves saw the arrival of the Union Army in Stafford, in April 1862, as a chance for freedom. During the Union occupation that spring and summer, slaves from Fredericksburg, Stafford, Spotsylvania, and surrounding counties streamed into Union lines. It was likely the largest single exodus of slaves in America up to that time.
(This picture of slaves seeking freedom is at Rappahannock Station [now Remington] on the Rappahannock River. From there they proceeded to Stafford.)