Timothy O'Sullivan was an early Western photographer. He served with Clarence King on the United States Geological Explorations of the Fortieth Parallel in 1867.
Timothy O'Sullivan (1840-1882) began his photography career as an apprentice to Mathew Brady, but he left the Brady gallery to photograph American Civil War battlefields on his own. In 1862 or 1863, he joined the studio of Alexander Gardner, who included forty-four of O'Sullivan's photographs in Gardner's Photographic Sketch Book of the War, the first published collection of Civil War photographs. His experience photographing in the field earned him a position as photographer for the Geological Exploration of the Fortieth Parallel, the first survey of the American West. He returned to Washington, D.C., in 1874 and made prints for the Army Corps of Engineers. Soon after being made chief photographer for the United States Treasury in 1880, O'Sullivan died of tuberculosis at age forty-one.
Several surveying expeditions funded by Congress were undertaken by the U.S. Army Corps of Engineers between 1869 and 1879, for the purpose of gathering data upon which to base a detailed topographic map. The expeditions were directed by Lt. George Montague Wheeler, and covered 359,065 square miles, including area within the states of New Mexico, California, Nevada, Arizona, Utah, Colorado, Idaho, Oregon, Wyoming, and Texas. In addition to the detailed topographic surveys, initial astronomic or geodetic points were established in Nebraska, Montana, and Washington Territory. These surveys are informally referred to as the Wheeler Survey.
American photographer.