Grant Marsh (May 11, 1834 – January, 1916) (also known as Grant P. Marsh, and Grant Prince Marsh) was a riverboat pilot and captain who was noted for his many piloting exploits on the upper Missouri River and the Yellowstone River in Montana from 1862 until 1882. He served on more than 22 vessels in his long career. He started his career in 1856 as a cabin boy and continued his career for over 60 years becoming a captain, riverboat pilot and riverboat owner. During his career he amassed an outstanding record and reputation as a river steamboat pilot and captain. His piloting exploits became legendary and modern historians refer to him as "Possibly the greatest steamboat man ever", "possibly the greatest [steamboat pilot] ever", "possibly the finest riverboat pilot who ever lived", "the greatest steamboat master and pilot on both the Missouri and Yellowstone Rivers"
After the discovery of gold in Montana Territory in the early 1860s, the Missouri River was the major artery for freight and passengers to go from "the states" to Fort Benton, the head of navigation in the territory. The last 300 miles ran through the unsettled prairie and the remote Missouri breaks. As a riverboat pilot on the upper Missouri River Marsh contended with migrating buffalo herds, hostile Indians, and violent windstorms, along with underwater hazards from rapids, snags and sandbars.
In the 1860s and 1870s The Yellowstone River, a tributary of the Missouri in the Montana Territory, penetrated deeply into an area dominated by the Sioux, Cheyenne and Crow tribes. From 1873 to 1879 Marsh piloted shallow draft paddle wheel riverboats making pioneer voyages up the Yellowstone River in Montana, in support of several military expeditions into Indian country. In 1875 he made the highest upriver ascent of the Yellowstone River in the Josephine arriving at a point just above present day Billings Montana.
Grant Marsh is most often referenced by historians for his exploit in 1876 as the pilot of the Far West, a shallow draft steamboat operating on the Yellowstone River and its tributaries, which was accompanying a U.S. Army column that included Lt. Colonel George Armstrong Custer and the 7th Calvary. The army column was part of the Great Sioux War of 1876, and its most noted battle was the Battle of the Little Bighorn, often known as "Custer's Last Stand" on June 25–26, 1876. After the battle, from June 30 to July 3, 1876 Grant Marsh piloted the Far West down the Yellowstone and the Missouri Rivers to Bismarck, carrying fifty one wounded cavalry troopers from the site of the defeat of Lt. Colonel George Armstrong Custer at the Battle of the Little Bighorn. He brought the first news of the "Custer Massacre" which was disseminated to the nation via telegraph from Bismarck. Most noteworthy in riverboat lore, Grant Marsh set a downriver steamboat record, traversing some 710 river miles in 54 hours.