12th Regiment, Pennsylvania Infantry (3 months, 1861)

Historical Sketch:
Col., David Campbell; Lieut. -Col., Norton McGiffin ; Maj., Alexander Hayes. This regiment, of which six companies were recruited at Pittsburg, two at New Castle and two in Washington county, was mustered into the U. S. service, April 25, 1861, at Harrisburg, to serve for three months. Several weeks were spent at York and on May 25 the regiment was ordered to guard the Northern Central railroad between the state line and Baltimore. Headquarters were made at Cockeysville and this laborious but important duty was faithfully performed by the troops until mustered out at Harrisburg on Aug. 5, 1861. Roster:
The Roster of this unit contains the names of 940 men.
Source:
The Union Army by Federal Publishing Company, 1908 - Volume 1
Bibliography:

Barcousky, Len. Civil War Pittsburgh: Forge of the Union. Charleston, South Carolina: The History Press, 2013. ISBN 9781626190818.

Blair, William and William Pencak, editors. Making and Remaking Pennsylvania's Civil War. University Park, Pennsylvania: Penn State University Press, 2004.

Fox, Arthur B. Our Honored Dead: Alleghany County, Pennsylvania, in the American Civil War. Chicora, Pennsylvania: Mechling Bookbindery, 2008.

Fox, Arthur B. Pittsburgh During the American Civil War 1860–1865. Chicora, Pennsylvania: Mechling Bookbindery, 2002.

Greater Chambersburg Chamber of Commerce. Southern Revenge: Civil War History of Chambersburg, Pennsylvania. Chambersburg, Pennsylvania: Greater Chambersburg Chamber of Commerce, 1989.

Miller, William J. The Training of an Army: Camp Curtin and the North's Civil War. Shippensburg, Pennsylvania: White Mane, 1990.

Sandou, Robert M. Deserter County: Civil War Opposition in the Pennsylvania Appalachians. Fordham University Press, 2009.

Skinner, George W., ed. Pennsylvania at Chickamauga and Chattanooga: Ceremonies at the Dedication of the Monuments Erected by the Commonwealth of Pennsylvania. Harrisburg, Pennsylvania: Wm. Stanley Ray, State Printer, 1897.

Taylor, Frank H. Philadelphia in the Civil War. Philadelphia, Pennsylvania: The City, 1913.

Wingert, Cooper H. Harrisburg and the Civil War: Defending the Keystone of the Union. Charleston, South Carolina: The History Press, 2013. ISBN 9781626190412.

Young, Ronald C. Lancaster County, Pennsylvania in the Civil War. Lancaster, Pennsylvania: published by the author, 2003.