In 1861 Coates was mustered in as a 1st lieutenant to the 1st Pennsylvania Reserve Regiment, also known as the 30th Pennsylvania Volunteer Infantry, Company C. Recruited out of Chester, Company C was first known as the "Keystone Guards" and then known for a time as the "Slifer Phalanx".[1]
Coates was promoted from 1st lieutenant to captain in 1862 and to Major by brevet in 1864.[3]
On June 13, 1864, Coates was mustered out with the company.[4]
Career
Coates was a member of the Delaware County bar.[5] He served as Postmaster of the Chester Post Office from 1865 to 1869[6] and as mayor of Chester from 1887 to 1893.[7] He was succeeded as mayor by John B. Hinkson.