Erica Armstrong Dunbar was flipping through Philadelphia newspaper archives from the turn of the 19th century when she uncovered something shocking.

“I came across the advertisement for a slave who had run away from the president’s house. I thought, ‘Who is this woman they’re referring to, Oney Judge?’ And, ‘Wait a minute! The president is advertising for a runaway slave? In Philadelphia? In 1796? Why don’t I know this story?’ ”

That encounter with Oney (who also went by Ona) was more than 20 years ago. Dunbar, of Wyncote, a professor of black studies and history at the University of Delaware, has spent nearly eight years coaxing Judge out of the shadows.

Dunbar tells the story in a new book, Never Caught: The Washingtons’ Relentless Pursuit of their Runaway Slave, Ona Judge (Feb. 7, Atria, $26). She’ll speak at the Central Library of the Free Library on Feb. 23. 

“I want to introduce the world to Ona Judge so that, hopefully, she will become a household name the same way that we know Frederick Douglass or Harriet Tubman,” Dunbar said. “Ona Judge predates all of them by decades. She predates even a loosely organized Underground Railroad.” 

Uncovering the story wasn’t easy work. Scholars of African American women’s history are used to scant sources; tracking a fugitive is even more vexing. ...