Oney Judge ran away from George and Martha Washington one day in May, 1796, while the First Family was in Philadelphia, the nation’s temporary capital. She was about twenty, enslaved since her birth at Mount Vernon—“a light mulatto girl, much freckled, with very black eyes and bushy hair,” according to a runaway advertisement in a local paper, “of middle stature, slender, and delicately formed.” Her father was a white indentured tailor, her mother a black seamstress, one of the nearly three hundred slaves Martha Washington had inherited after the death of her first husband. There had been “no suspicion of her going off, nor no provocation to do so,” the ad stated, with an aggrieved note; Judge had been Martha’s personal servant, and was a particular favorite of hers. But the Washingtons knew that slaves could claim their freedom after six months on Pennsylvania soil, and had been careful to deny theirs the chance by regularly taking them out of state. Judge had made her escape just before they planned to travel home to Virginia. She was found in Portsmouth, New Hampshire, where the customs collector interviewed her at Washington’s behest. “A thirst for compleat freedom,” he reported, “had been her only motive for absconding.”...