(1812 - 1887)
Home State: Massachusetts
Education: US Military Academy, West Point, NY, Class of 1832;Class Rank: 29th
Command Billet: Inspector General, AOP
Branch of Service: Infantry
Unit: Army of the Potomac
On Graduation from West Point, July 1, 1832, he was brevetted a second lieutenant in the Fifth Infantry, perm 2nd. Lt 25 November 1835, 1st Lt 22 June 1837, and to Captain on 18 May 1846. With the exception of two brief tours as a recruiting officer in the East, he spent this period on the northwest frontier in Michigan and Wisconsin.
During the Mexican War he saw action at the battles of Palo Alto and Resaca de la Palma. Again detached for recruiting duty, Marcy returned to Texas in 1847, and in 1849 he determined the route of the Marcy Trail, from Fort Smith to Santa Fe. In 1851 he commanded Gen. William G. Belknap's escort on the tour that selected the sites for forts on the Texas frontier.
In March 1852 Marcy was assigned the command of a seventy-man exploring expedition across the Great Plains in search of the source of the Red River and directed to "collect and report everything that may be useful or interesting." Second in command of the Marcy expedition was Capt. George B. McClellan. Marcy's 1852 expedition has been called the most significant of his career and "the best organized, best conducted, and most successful" venture into the region to that date.
With the outbreak of the Civil War, he was promoted to Colonel and named Inspector General of McClellan's Army of the Potomac. From September 23, 1861, through July 17, 1862, and again from September 13, 1862, through March 4, 1863, he served as acting Brigadier General of Volunteers.
On the Campaign
He served as General McClellan's Chief of Staff on the Campaign, and was with General Hooker for much of the battle of Antietam on 17 September 1862.
After the War
From 1863 through 1878 he served as Inspector General of various departments of the army, and on December 12, 1878, he was promoted to the regular rank of Brigadier General and was named Inspector General of the US Army. He retired from the army on January 2, 1881
References & notes
He was Gen McClellan's father-in-law. McClellan married Marcy's daughter Mary Ellen on May 22, 1860.
Sources: Heitman, Francis Historical Register and Dictionary of the United States Army 1789-1903, Washington, US Government Printing Office, 1903.; and
a biography from The Handbook of Texas Online, from UTexas. The photo above is from a CDV offered for sale by Jeff Krauss.
4/9/1812; Greenwich, MA
11/22/1887; West Orange, NJ; burial in Riverview Cemetery, Trenton, NJ