John Gross Barnard (May 19, 1815 – May 14, 1882) was a career engineer officer in the U.S. Army, serving in the Mexican–American War, as the superintendent of the United States Military Academy and as a general in the Union Army during the American Civil War.Warner, Ezra J., Generals in Blue, pp. 19–20. Louisiana State University Press, Baton Rouge, 1964. . He served as Chief Engineer of the Army of the Potomac, 1861 to 1862, Chief Engineer of the Department of Washington from 1861 to 1864, and as Chief Engineer of the armies in the field from 1864 to 1865.Eicher, John H. and Eicher, David J., Civil War High Commands, p. 116. Stanford University Press, Stanford, CA, 2001. ; Warner, 1964, pp. 19–20 He was also a distinguished scientist, engineer, mathematician, historian and author.Cullum, George W., George W. Cullum's Register of Officers and Graduates of the United States Military Academy, Vol. I, 1891, p. 533, as retrieved October 12, 2010, from the web site http://penelope.uchicago.edu/Thayer/E/Gazetteer/Places/America/United_States/Army/USMA/Cullums_Register/708*.html

Early life and career John G. Barnard was born into a large and gifted family in Sheffield, Massachusetts.Warner, 1964, p. 19 for birth date and place. His brother, Frederick Augustus Porter Barnard was a longtime educator and president of Columbia University and namesake of Barnard College in New York City.New York Times obituary, April 26, 1889 Both John and Frederick, as well as most members of their family, suffered from a hereditary form of deafness which intensified in later years.Warner, 1964, p. 19 refers to his "inherited deafness." In early life, when stationed in New Orleans, Barnard married Jane Elizabeth Brand, of Maryland, with whom he had four children. In 1860, he married Anna E. Hall of Harford County, Maryland, with whom he had three children.Abbot, Henry L., Biographical Memoir of John Gross Barnard, 1815–1882, p. 9 (227), Read before the National Academy of Sciences, April 17, 1902. http://books.nap.edu/html/biomems/jbarnard.pdf, retrieved October 12, 2010. This paper was included in a book of biographical sketches published by the National Academy of Sciences as the page number in parentheses indicates. The exact title of the book is not given in the web download which only contains the Abbot paper of 11 pages.

In 1833, at the age of 18, Barnard graduated from the United States Military Academy at West Point, New York, second in a class of forty-three cadets.Eicher and Eicher, 2001, p. 116, Cullum, 1891, pp. 530, 533 As one of the top graduates of his class, he was posted as a Second Lieutenant in the United States Army Corps of Engineers, embarking on a 48-year career in that branch.Sifakis, Stewart, Who Was Who in the Civil War p. 33. Facts On File, New York, 1988. .

Barnard's first assignment after being commissioned was as an assistant to Colonel Joseph G. Totten in constructing Fort Adams in Newport, Rhode Island, from 1833 to 1834. Totten was the foremost American military engineer of his day and served as Chief Engineer of the Army for much of Barnard's career. There, the two formed a close friendship as evidenced by Barnard's extensive eulogy of Totten, which was published in 1866.

Throughout his career, Barnard served on many garrison and fortification details, most notably participating in the construction of coastal defenses at Fort Columbus/Fort Jay, Fort Hamilton and Fort Wadsworth in New York City, New Orleans, Pensacola, Mobile, Fort Livingston, Louisiana, Fort Jackson, Louisiana, Fort St. Philip, Louisiana and on the Pacific Coast at San Francisco.Warner, 1964, pp. 19–20 refers to fortifications on the Atlantic Coast, Pacific Coast, Delaware, breakwater and New York City. During the Mexican–American War, he headed the construction of American defenses at the captured Mexican port of Tampico,Warner, 1964, p. 20 ensuring that city's safety as a vital supply line for American forces advancing on Mexico City. He also worked on the survey of Mexican–American War battlefields. and as chief engineer for the Exploration and Survey of the projected Tehuantepec Railroad in Mexico, in 1850–1851.Cullum, 1891, p. 530

From May 31, 1855, through September 8, 1856, Barnard served as the Superintendent of the United States Military Academy,Eicher and Eicher, 2001, p. 116 succeeding Robert E. Lee.Warner, Ezra J., Generals in Gray, p. 181. Louisiana State University Press, Baton Rouge, 1959. . He then returned to work on coastal defenses, especially in the New York and New Jersey area. During a leave of absence, he studied construction projects in Europe.

Civil War Soon after the outbreak of the Civil War, U.S. Army commander Major General and Brevet Lieutenant General Winfield Scott, bearing in mind Barnard's success at defending his Tampico-based supply lines during the Mexican–American War, assigned then Major Barnard to the Department of Washington. This was the Union Army unit in charge of defending Washington, D.C., the capital of the United States. On April 28, 1861, Colonel Joseph K. Mansfield, the department commander, a former engineer himself, attached Barnard to his headquarters as chief engineer.Sifakis, 1988, p.33; General Orders No. 11, Department Of Washington, April 28, 1861.

When the Union Army moved into Northern Virginia on May 24, 1861, Barnard oversaw the erection of fortifications on the Arlington hills.Sifakis, 1988, p. 33 He also accompanied the Army to Manassas in July 1861 and was present at the Union defeat at the First Battle of Bull Run (Manassas). Between June 1861 and September 1861, Barnard also served on the U.S. Navy's Blockade Strategy Board. Major General George B. McClellan assumed command of the Military Division of the Potomac, the troops around Washington, D.C., on July 23, 1861.Sifakis, 1988, p. 406 On August 15, 1861, McClellan was appointed to the command of the Army and Department of the Potomac, and Barnard became chief engineer of the Military District of Washington.On August 17, all the troops in the vicinity of Washington became part of the Army of the Potomac. Three days later, General Orders No. 1, Army of the Potomac, stated that Barnard was attached to the staff as chief engineer. As McClellan formulated his thoughts for fortifications around Washington, D.C., Barnard planned, designed and oversaw their construction.

In Barnard's A Report on the Defenses of Washington, published after the Civil War, he commented on the complexity and ever-changing nature of the project:

From a few isolated works covering bridges or commanding a few especially important points, was developed a connected system of fortification by which every prominent point, at intervals of 800 to 1,000 yards, was occupied by an inclosed field-fort every important approach or depression of ground, unseen from the forts, swept by a battery for field-guns, and the whole connected by rifle-trenches which were in fact lines of infantry parapet, furnishing emplacement for two ranks of men and affording covered communication along the line, while roads were opened wherever necessary, so that troops and artillery could be moved rapidly from one point of the immense periphery to another, or under cover, from point to point along the line."A Report on the Defenses of Washington," Barnard, John G. 1871

On September 23, 1861, President Abraham Lincoln appointed Barnard to the grade of brigadier general, U.S. Volunteers, to rank from September 23, 1861.Eicher and Eicher, 2001, p. 718 Lincoln formally nominated Barnard as brigadier general on December 21, 1861, and the U.S. Senate confirmed the promotion on March 24, 1862. Barnard was engineer for the Army of the Potomac between August 20, 1861, and August 16, 1862. He participated in the Peninsula Campaign and directed the siege works at Yorktown, Virginia and later the offensive and defensive works on the Chickahominy River. On the march to Harrison's Landing on the James River, he reconnoitered and selected positions for the Battle of Gaines Mill, the passage of White Oak Swamp and the Battle of Malvern Hill. After the conclusion of his work in that campaign, he again was engaged in working on the defenses of Washington as chief engineer of the Department of Washington until May 1864. He had certain additional special assignments, such as devising the defenses of Pittsburgh, Pennsylvania, during this period.Eicher and Eicher, 2001, p. 116; Sifakis, 1988, p. 33; Cullum, 1891, p. 531

Upon the death of the Chief of the U. S. Army Corps of Engineers, Brigadier General Joseph Totten, on April 22, 1864, President Lincoln nominated Barnard to be the next Chief of the U.S. Army Corps of Engineers at the grade of brigadier general, U.S. Army, but Barnard immediately asked that the nomination be withdrawn.Eicher and Eicher, 2001, p. 116. The promotion went to 65-year-old Colonel Richard Delafield instead. Delafield had been working on New York Harbor defenses. He was promoted to Chief of the Corps of Engineers with the rank of brigadier general to rank from April 22, 1864, on May 19, 1864. Warner, 1964, p. 118. Delafield was a Regular Army colonel and as such was senior to Barnard who was a Regular Army lieutenant colonel. Henry Larcom Abbot, Barnard's aide-de-camp in the Peninsula campaign and himself a brevet brigadier general, USA, brevet major general, USV, and colonel in the Army Corps of Engineers upon his retirement in 1895, suggested in a 1902 paper that Barnard's sense of justice probably made him feel that he should not take a promotion over an officer superior in rank at the time. Abbot, 1902, p. 9 (227); for Abbot information see Abbot, 1902, p. 10 (228); Hunt, Roger D. and Brown, Jack R., Brevet Brigadier Generals in Blue, p. 1. Olde Soldier Books, Inc., Gaithersburg, MD, 1990. ; Eicher and Eicher, 2001, p. 97

Barnard was Engineer XXII Corps, Department of Washington, between February 2, 1863, and May 25, 1864. Between May 25, 1864, and June 5, 1864, he was chief engineer for the Army of the Potomac. He was on the staff of General Ulysses S. Grant in the Overland Campaign between June 5, 1864, and July 4, 1864. On July 4, 1864, President Lincoln nominated and the U. S. Senate confirmed the award to General Barnard of the honorary rank of brevet major general, U.S. Volunteers, to rank from July 4, 1864, for "Meritorious and Distinguished Services during the Rebellion."Eicher and Eicher, 2001, p. 710; Cullum, 1891, p. 531

Barnard was appointed chief engineer of the armies in the field with his appointment to General Grant's staff. He remained in this position during the Siege of Petersburg, including the capture of Fort Harrison, the Battle of Hatcher's Run and the final assault on Petersburg, until the surrender of the Army of Northern Virginia at Appomattox, Virginia, on April 9, 1865.

General Barnard served in the honor guard for President Lincoln's funeral in April 1865. He was mustered out of the U.S. Volunteers on January 15, 1866.

On April 10, 1866, President Andrew Johnson nominated and on May 4, 1866, the U.S. Senate confirmed the award to Barnard of the honorary grade of brevet brigadier general, USA, (Regular Army) to rank from March 13, 1865, for "Gallant and Meritorious Service in the Campaign terminating with the Surrender of the Insurgent Army under Gen. R. E. Lee."Eicher and Eicher, 2001, p. 732, Cullum, 1891, p. 531 On July 17, 1866, President Johnson nominated and on July 23, 1866, the U.S. Senate confirmed the award to Barnard of the honorary grade of brevet major general, USA, to rank from March 13, 1865 "for Gallant and Meritorious Services in the Field during the Rebellion."Eicher and Eicher, 2001, p. 706, Cullum, 1891, p. 532

Postbellum career