Philadelphia's enlistments since the attack on Fort Sumter approach ten thousand
Authorities announced that Philadelphia had since the firing on Fort Sumter enlisted 9,600 men in all. The War Department's assessment for troops on April 15, 1861 was sixteen regiments from Pennsylvania; Philadelphia's share was to have been six regiments, or around 5,000 men. (By John Osborne)
Thomas Scharf and Thompson Wescott, History of Philadelphia 1609-1884, in three volumes (Philadelphia, PA: L.H. Everts & Co., 1884), I: 760.