The term, “Union Rifles,” was the designation given to the combined troop strength of two militia units of the Lehigh Valley in Pennsylvania: the Jordan Artillerists, led by William H. Gausler, and the Allen Rifles, commanded by Tilghman H. Good, the founder of the 47th Pennsylvania Volunteers who would be elected mayor of Allentown following the Civil War.
According to Lewis Schmidt in his A Civil War History of the 47th Regiment of Pennsylvania Veteran Volunteers, the Allen Rifles and the Jordan Artillerists “combined their forces as the Union Rifles,” following a 13 April 1861 decision by the citizenry of Lehigh and Northampton counties to form a new military unit – the 1st Regiment, Pennsylvania Volunteer Infantry – following the fall earlier that day of Fort Sumter to the Confederate Army.
The Allen Rifles and Jordan Artillerists effected this merger “to meet the request of the state that units arriving should have at least 100 men on their muster.” The men of both local militia mustered in jointly at Camp Curtin in Harrisburg on 20 April 1861, becoming Company I of the newly formed 1st Pennsylvania Volunteers.
Source: Schmidt, Lewis. A Civil War History of the 47th Regiment of Pennsylvania Veteran Volunteers.