Coates enlisted in the Union Army on September 4, 1861. He was
commissioned as a Captain with Company I, New Jersey 10th Infantry
Regiment on November 26, 1861.
William Bryan of Beverly, New Jersey recruited and organized
this regiment which was known as the "Olden Legion". John Y. Foster,
whose history of New Jersey' Civil War units written in 1868, states
that "On the first roster of the regiment, after being placed in State service, is this endorsement: "This regiment was raised by individuals, not authorized by the State, and accepted by the War Department as an independent organization, some time in the fall of 1861, and was not known by the State authorities until it was placed under their care, January 29,
When the organization of the regiment was completed with nine companies of infantry and one company of cavalry, it was established at Camp Beverly, New Jersey where William Bryan lived. The unit proceeded to Washington, D.C., on December 26, 1861, with 35 officers, 883 non-commissioned officers and privates, for a total of 918 men.
After they marched to Camp Clay on the Bladensburg Turnpike, a location approximately one mile from Washington, they were reorganized and designated the 10th New Jersey Infantry. Soon after being reorganized the cavalry company, Company D, was discharged and a new company was raised that April. In fact, the regiment was not very effective by February 1862 when many of the cavalry company were under arrest for refusing to do infantry duties
Coates mustered out on March 6, 1862.
Coates was a member of the G.A.R.,
belonging to Thomas M.K.
Lee Post No. 5 of the G.A.R., where his son John W. Coates was
also a member, having served for over 3 years as a Private in
Company B, 3rd New Jersey Infantry.
1863 City Directory shows John Coates at 124 West
Street, where he was still living in November of 1899. The
Census of 1870 shows John Coates living with his wife and three
children. John W., 30, Lewis C., 24, and Frances, 18. The 1880
Census shows John Coates, his wife Rebecca and sons John W. and
Lewis C. Coates living at 124 West
Street. Daughter Frances had married Dr. Onan B. Gross, a
prominent Camden physician. John W. Coates worked with his father
as a bricklayer, while Lewis was a grocer.
February of 1899 John Coates son John W. Coates died suddenly
while visiting his sister Frances and her husband, Dr. Onan B.
Gross, at their home at 700 Market
Street. Still living at 124 West
Street and conducting his real estate business in November of
1899, John Coates reported a robbery in his home. This proved not
to have been the case. John Coates moved in with his daughter and
son-in-law shortly thereafter.