Ohio.org:
The Gammon House was built in 1850 – the same year that the Fugitive Slave Act of 1850 imposed six months’ imprisonment and a massive $1,000 fine on any person aiding a runaway slave by providing food and shelter. Originally owned by a black abolitionist named George Gammon, the famous stop features secret passages leading into the attic and a tunnel into the basement. The Gammon House is one of only three existing Ohio “stops” on the Underground Railroad owned by a free person.