However, he withdrew when he received an appointment to the United States Military Academy in West Point, New York, on July 1, 1843.

[2] With the Mexican War raging, he was assigned to garrison duty at Tampico, Mexico, where he contracted yellow fever.

After the departure of Edward O. C. Ord, Mason assumed the role of post commander at Fort Vancouver on May 7, 1861, and remained in that position until June 11, when relieved following the arrival of Capt.

In 1862, Mason's regiment participated in the Peninsula Campaign of Maj. Gen. George B. McClellan, where they guarded Harrison's Landing.

Late in the year, he commanded a brigade in Maj. Gen. John Sedgwick's II Corps' "Right Grand Division" and fought at the Battle of Fredericksburg.

His health, never robust following the two yellow fever bouts, again failed him and Mason asked for and received administrative duty.

[5] In the omnibus promotions at the end of the Civil War in 1865, he was brevetted through the Regular Army grades to that of brigadier general.

[6] He retired in 1888 as the colonel of the 9th U.S. Infantry at Fort Whipple, Arizona, and took up residence in Washington, D.C., where he died at home on November 29, 1897, from general paralysis brought about from a stroke.

[7] One of his sons, Captain John S. Mason Jr., perished at the army post at the Pine Ridge Indian Reservation from exposure in the line of duty, and is also buried at Arlington National Cemetery.