Camp William Penn: 1863-1865Located in Chelten Hills just outside of Philadelphia, Pennsylvania, Camp William Penn was the largest and first Civil War facility to exclusively train Northern based federal black soldiers during the war. Boasting the biggest free black population in the country and the 19th centurys epicenter of the Underground Railroad, Philadelphia and Camp William Penn, hosted the greatest anti slavery abolitionists, including Frederick Douglass, Harriet Tubman,