National Park Service: Visit Underground Railroad Locations
The Filson Historical Society founded in 1884 “is a privately-supported historical society dedicated to preserving the history of Kentucky and the Ohio Valley Region.”
“Cincinnati’s Role in the Underground Railroad” (3:21) YouTube, March 1, 2007
A video by the National Underground Freedom Center explains how geography, Margaret Garner, the presence of Lane Seminary, and the activity of prominent abolitionists including Harriet Beecher Stowe shaped history.
Gary Pyles. “Louisville Slavery” (2:35) YouTube, March 4, 2013
Interviews with scholars describe this city’s slave trade along the Ohio River as well as the flight to freedom across this river.
1st U.S. Colored Cavalry 
It looks like your map left out a peak area in South Central Pennsylvania. An area outside of a little town in Mercersburg, Pa. called “Little Africa” harbored hundreds of former slaves. Ira Brown who wrote The Negro History of Pa. wrote about hundreds fleeing from the area when the cofererates came through. Charles Blockson also wrote about the Mercersburg area in his Underground Railroad” books.
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Hi, Maryann — Thanks for your comment. This map shows locations on the National Park Service’s “Network to Freedom.” Information about the initiative and how to nominate a site is available at its homepage https://www.nps.gov/subjects/ugrr/index.htm.
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