Conductors on the Underground Railroad —both black and white—risked life and limb to move runaway slaves from one station to the next. Some were ex-slaves driven by hatred of the bondage system. Many were Quakers following deeply held religious beliefs. Others were simply common citizens appalled by slavery.

With the enactment of the Fugitive Slave Act in February 1793, aiding runaway slaves became a federal offense. Anyone who harbored an escaped slave or prevented his or her arrest could be fined $500—a considerable sum of money at that time. In 1850, that penalty was boosted to $1,000—a huge amount that would bankrupt almost anyone who was forced to pay it.

Because of this, according to Henrietta Buckmaster in the 1941 book Let My People Go,

Conductors learned very early on the advantage of discretion; many times information was conveyed from...