Phinehas Merrill (1767 - March 31, 1815) was an American educator, mathematician, surveyor and cartographer active in New Hampshire during the late 18th and early 19th century. Merrill was well known throughout New Hampshire as a surveyor. His survey work brought him to the attention of Philip Carrigain, then New Hampshire's Secretary of State. Carrigain was in the process of creating a large scale map of New Hampshire and Merrill surveying skills were essential to completing the project. Working together, Merrill and Carrigain completed numerous new surveys, check old surveys, and slowly pieced together a new monumental map of the state. The Carrigain Map of New Hampshire, as it came to be known, was completed in 1814, but not published until 1816, one year after Merrill's death. The devoted surveyor never saw his completed masterpiece. More by this mapmaker...

William C. Margedant (November 15, 1835 - January 12, 1900) was a German-American engineer and U.S. Army soldier. Born in Dusseldorf, Germany (then Prussia), Margedant was educated in Germany and immigrated to the United States in 1854. He settled in Cincinnati, Ohio, where he was employed by C.A. Latta and assisted in constructing the first steam fire engine in the United States. He then started working as a machinist in Hamilton, Ohio, in the shops of Owens, Lane, and Dyer and eventually began working for the Bentel and Margedant Company, which designed and manufactured wood working machinery. In 1861, Margedant volunteered to serve in the Union army and organized a company of forty-eight volunteers from Hamilton. This company then joined the Ninth Ohio Volunteer Infantry in Cincinnati and Margedant was elected captain of his unit. Margedant, after his first three month enlistment was up, was appointed to the topographical engineers on the staff of General William Starke Rosecrans (September 6, 1819 – March 11, 1898). He was involved in the organization and compilation of the first detailed topographic maps of West Virginia. While serving on Rosecrans's staff, Margedant

invented method of duplicating maps in the field by which all corps, divisions and brigades, as well as individual regiments when acting or moving alone, were furnished at each camp with maps of the surrounding country on the march, with those showing the roads, streams and other military features of country in advance. These maps were printed on cloth, often on a handkerchief and distributed in great numbers. Photographic duplications of charts gave valuable information as to camp grounds, water forage, kind of roads and trails and their condition. Every organization down to brigades had a topographical engineer whose business it was to gather daily all the information possible of the country where the troops halted, and of the region in advance, and reported it in the evening to the next superior headquarters. At army headquarters Capt. Margedant's force consolidated the topographical notes received, and the next day maps and charts containing everything ascertained the day before were in the hands of all commanding officers.

Because of this service, Margedant came to be known as 'the pathfinder of the Army of the Cumberland.' Margedant then served on the staff of General John C. Fremont and saw combat in multiple battles. Margedant remained in the army until late 1864, when he fell seriously ill from typhoid fever. During his time in the army he participated in thirty-six battles and engagements, from West Virginia through the Shenandoah Valley, Tennessee, Georgia, and Alabama. Margedant remained active after the war, becoming a member of the Grand Army of the Republic and a staunch Republican. He was a figure in the community, a liberal giver of both time and money. He also served as the president of the Pioneers', Soldiers' and Sailors' Permanent Monument Association. Margedant married Caroline Son on January 28, 1864, with whom he had nine children. Learn More...

Army Corps of Topographical Engineers (fl.1838 - 1863) refers to the an elite branch of the U.S. Army created on July 4, 1838 to perform civil mapping and survey work throughout the United States. The origins of the Corps of Topographical Engineers can be traced back to the American Revolutionary War, where General George Washington recognized the need for accurate surveys pursuant to military action. Shortly following the war, in 1779, a civilian engineering corps was created by act of Congress. Identified in 1802 by Thomas Jefferson, the "Corps of Engineers," which was based at West Point, the group participated in the War of 1812 and in later in the fortification of New Orleans. It was not until 1838, however, that a separate group of "Topographical Engineers" was formally recognized. This elite group, consisting only of officers, most of whom were trained in surveying and engineering by the esteemed Andrew Ellicott at West Point, never numbered more than 36 individuals - the best and brightest. This small but determined group played a central role in the mapping and exploration of the American West. Few branches of the military can boast such a distinguished alumni. Their names resonate throughout the map of the west and include John Charles Fremont, Zebulon Pike, George Meade, Kemble Warren, William Amiel Weeks, A. B. Gray, Randolph B. Marcy, James H. Simpson, Howard Stansbury, John W. Gunnison, William Ludlow, and Robert S. Williamson. The onset of the American Civil War brought an abrupt end to the surveying activity of the Topographical Engineers. Many of the most prominent engineers went on to distinguished military careers on both sides of the War Between the States. The Army Corps of Topographical Engineers itself was folded into the Corps of Engineers on March 31, 1863. Though the Army Corps of Engineers continues to do military and civil survey work to this day, the elite club of adventures that formed the Topographical Engineers were no more. Learn More...