These acts were statutes passed by Congress to legalize the capture and return of fugitive slaves. Since fleeing slaves usually headed North (duh) they were basically rules for extradition that stripped any right of defense from the slaves. Slaves were not allowed a trial by jury or to act in their own legal defense.

The reaction to these acts was expansive. Many of the Northern states made laws to defend the rights of escaped slaves (which incidentally were named by many Southern states as the official reason for their secession.) The Underground Railroad kicked into high gear and abolitionists were galvanized into action.

The adoption of the Fugitive Slave Acts started in 1850 and were not repealed until 1864.