John enlisted in the spring of 1779, while living
in Mayfield, as a private in Captain John Littel's Company in Colonel Frederick
Visscher's Regiment of Tryon County Militia [Third Regiment]. John with his
brother Ebenezer moved to Fort Johnstown where they were stationed.
In May of 1780, John enlisted as a sergeant in Captain Garret Putman's Company in Colonel John Harper's Regiment of New York State Levies.
John was stationed at Fort Plain, Herkimer, House, Paris, Plank and Johnstown. John was discharged at Fort Herkimer on January 1, 1781.
On May 8, 1781, John enlisted as a private in Captain Lawrance Gros' Company in Colonel Marinus Willett's Regiment of New York State Levies. John was stationed at Fort Rensselaer (Fort Plain).
On September 6th, John under Lieutenant Solomon Woodworth left Fort Rensselaer and marched to Fort Dayton where they spent the night. In the morning of September 7th, John under Lieutenant Woodworth went out on a scout along the West Canada Creek.
After marching about ten miles the scouting party fell into an ambush by a party of Indians and Loyalists under Lieutenant Jacob Clement. After about ten minutes of fighting Lieutenant Woodworth, Dunham and twenty three others were killed. Eight men were taken prisoners and about fifteen escaped back to Fort Dayton.
On September 8th, Captain Garret Putman with his company and some of the survivors from the ambush of the day before returned to the site of the ambush and buried Dunham and the others in one grave and then they returned to Fort Dayton.