The Christiana Incident offers a snapshot of the U.S. when the country was sorting into states where slavery was upheld and states that had abolished it, and what racist tension looked like at border states in the mid-1850s.
Research:

James Braid, Surgeon and Father of Hypnotism
43:36

Gladys Bentley
40:09

SYMHC Classics: Moms Mabley
33:10