William Emery Merrill (1837-1891) was an American soldier and military engineer. He was born at Fort Howard, Wisconsin, and was
a cadet at West Point beginning in 1854. After graduating first in his class in 1859, he served as an instructor in engineering
at West Point until mid-1861 when Merrill was called into active duty in the Civil War.
He first served as Assistant Engineer, Department of the Ohio, from July 15 to September 12, 1861, and was engaged in fortifying
Red House, Maryland, and Cheat Mountain and Elk Water, West Virginia. He was a prisoner of war from September 12, 1861 to
February 23, 1862 (except November 10-11, 1861) when he escaped and was recaptured. He then served as Assistant Engineer,
Army of the Potomac in the Peninsular Campaign from March to April 1862 during the Siege of Yorktown. He took an injured leave
of absence from April 16 to May 12 1862 and returned to duty in the temporary charge of the defenses of Washington, DC, May 15
to June 30, 1862. Merrill was then transferred to Kentucky and served as Superintending Engineer of the Defenses of Newport and
Covington where he was engaged in the construction of the Defenses of the Kentucky Central Railroad, November 1862 to March 1863
and in charge of the Topographical Department of the Army of the Cumberland. He served as Chief Engineer of the Army of the
Cumberland. Merrill and his team's mapping of Georgia prior to Sherman's March to the Sea was intstumental to the campaign's success.
For a more complete look at Merrill's history, refer to United States Military Acadamy Library's digitizied Biographical register
of the officers and graduates of the U.S. Military Academy at West Point, N.Y., from its establishment, in 1802, to 1890: With the
early history of the United States Military Academy, Volume II, pages 714 and 715
(http://digital-library.usma.edu/cdm/pageflip/collection/p16919coll3/id/15955/type/compoundobject/filename/print/page/download/start/717/pftype/pdf).
In March 1867, he was raised from the regular army rank of captain to major and in February 1883 to that of lieutenant colonel.
From 1867 to 1870 he served as chief engineer on the staff of General Sherman, then in command of the Military Division of the Missouri,
and thereafter until his death he was engaged on engineering work for the government. One of the most notable engineering works was the
Chanoine wicket movable dam constructed by him at Davis's Island, 5.5 miles below Pittsburgh, Pennsylvania. The Davis Island Lock and
Chanoine Dam experimental project was the first lock and dam ever constructed on the Ohio River. Its achievements also included the
first rolling lock gates, the largest movable dam built in the 19th century, and the widest chamber in world history. In 1889, Merrill
represented the United States Engineering Corps at the International Congress of Engineers in Paris. He died in 1891.
