History of Northumberland County, Pennsylvamia by Herbert C. Bell
Chicago: Brown, Runk & Co., Publishers c.1891 p.902-3

Colonel Alexander Caldwell was one of the bravest and most efficient soldiers that ever went out from thi county in defense of the Union during the dark days of civil strife. He was born in Shamokin, Pennsylvania, February 19, 1840, son of Alexander and Martha Caldwell, early settlers of that town. Alexander grew up in his native place, and received such education as the schools of that time afforded. He taught school at intervals and attended academies at Millville and Tuscarora, Pennsylvania several terms. He was a well read man and possessed a very retentive memory. Returning from school to respond to the first call for troops, he enlisted in Company A, 8th Pennsylvania Volunteers and served as a drummer boy in the three months service. He re-enlisted in Co. K, 46th Pennsylvania Volunteers for three years and was mustered in as first sergeant, was promoted to 2nd Lieutenant, November 1, 1861 and to 1st lieutenant on the battlefiend at Cedar Mountain August 9, 1862, and to captain of his company November 1, 1862. He served in all the battles and campaigns of his regiment, and veteranizing at the expiration of his three years' service, he took part in the closing scenes of the war, and participated in the Grand Review at Washington, D.C. May 24, 1865. He was mustered out of service with the rank of captain, July 16, 1865. Returning from the was he located in Shamokin, where he was married September 11, 1867 to Mary L, eldest daughter of Richard B. Douty, of which union five children were born. Richard A.; Catherine; Grace, deceased; Frederick C., and Ralph M. Colonel Caldwell raised a company in Shamokin which was mustered into the National Guard and afterwards he rose to the rank of Colonel of the 7th regiment, N.G.P. For several years he was the local agent of the Northern Central Railway Co., in Shamokin, and afterward filled the office of notary public and pension agent very successfully up to his death.

Politically, he was a stalwart Republican, and was a thorough soldier in thought and deed. He died December 15, 1886, and a monument to memory and gallant deeds has been erected in the Shamokin Cemetery by his comrades in the G.A.R.