Decades before the Civil War, Illinois's status as a free state beckoned enslaved people, particularly those in Kentucky and Missouri, to cross porous river borders and travel toward new lives. While traditional histories of the Underground Railroad in Illinois start in 1839, and focus largely on the romanticized tales of white men, Larry A. McClellan reframes the story, not only introducing readers to earlier freedom seekers, but also illustrating that those who bravely aided them were Black and white, men and women. McClellan features dozens of individuals who made dangerous journeys to reach freedom as well as residents in Chicago and across northeastern Illinois who made a deliberate choice to break the law to help.

Onward to Chicago charts the evolution of the northeastern Illinois freedom network and shows how, despite its small Black community, Chicago emerged as a point of refuge. The 1848 completion of the I & M Canal and later the Chicago to Detroit train system created more opportunities for Black men, women, and children to escape slavery. From eluding authorities to confronting kidnapping bands working out of St. Louis and southern Illinois, these stories of valor are inherently personal. Through deep research into local sources, McClellan presents the engrossing, entwined journeys of freedom seekers and the activists in Chicagoland who supported them.

McClellan includes specific freedom seeker journey stories and introduces Black and white activists who provided aid in a range of communities along particular routes. This narrative highlights how significant biracial collaboration led to friendships as Black and white abolitionists worked together to provide support for freedom seekers traveling through the area and ultimately to combat slavery in the United States.