John L. Tiernon (January 18, 1841 – March 30, 1910) was a career officer in the United States Army.

[2][3] When the Speaker of the House, George M. Pinney, resigned in early 1862, Tiernon was elected to complete his term.

[4] When the army established Fort Reynolds on Angel Island, California in September 1863, it was garrisoned by Battery B, 3rd Artillery Regiment.

[5] As the battery's commander, Tiernon named the post in honor of John F. Reynolds, a Union Army general who had been killed at the Battle of Gettysburg.

[5] As the war neared its conclusion, Tiernon was reassigned to provost marshal duties in New Mexico Territory.

[4] After the war, Tiernon remained in the service and served as assistant commissary of subsistence for the 3rd Heavy Artillery Regiment at Fort Independence, Massachusetts.

[6] In 1868, he was assigned as Ordnance officer on the staff of the newly organized U.S. Army Artillery School at Fort Monroe, Virginia.

[18] He was subsequently appointed as chief of the Manila police, and he served until returning to the United States in late 1901.