In 2006, he published Blacks on the Border: The Black Refugees in British North America, 1815-1860. Whitfield has written several articles about free black communities in Nova Scotia. His most recent articles explore slavery in the Maritime Colonies. He is the author of numerous encyclopaedia entries and book reviews. Whitfield has presented academic papers at the Canadian Historical Association, American Historical Association, SHEAR, and the Harriet Tubman Centre. He is currently working on a project about slavery and black citizenship in Revolutionary Vermont.