Almon Thompson

Almon Harris Thompson
Thompson in 1902
Born	September 24, 1839 Stoddard, New Hampshire
Died	July 31, 1906(1906-07-31) (aged 66)
Nationality	American
Spouse	Ellen Powell Thompson

Almon Harris Thompson (September 24, 1839 – July 31, 1906), also known as "A. H. Thompson", was an educator, topographer, geologist, explorer, and Civil War veteran. Often called "The Professor" or simply "Prof", Thompson was second in command of John Wesley Powell's Second Expedition, a federally funded expedition to explore the Green and Colorado Rivers, Colorado drainage and canyons, and map southern Utah and northern Arizona. Thompson's diary of Powell's Second Expedition (1871–1875) was originally published in the Utah Historical Quarterly in 1939. Through his work on the Powell expeditions and later as geographer at the US Geological Survey, he was responsible for naming many geographic locations in the west. Thompson is also known for his involvement in the formation of the National Geographic Society.

Thompson was born on September 24, 1839 in Stoddard, New Hampshire. Later, his family moved to Southborough, Worcester, Massachusetts (1848–1856) where he attended school. Thompson enjoyed mathematics and science. Thompson attended Wheaton College (1857–1861) in Illinois where he met John Wesley Powell. After graduation, he married Ellen Louella (Nellie) Powell (1840–1909), the sister of John Wesley Powell on July 8, 1862 in Wheaton, Illinois. They had no children.

On May 16, 1864, Almon H. Thompson enlisted in the United States Army noting his residence as Hennepin, Illinois. He was commissioned as an lieutenant in Company B, 139th Illinois Volunteer Infantry Regiment on June 1, 1864. Thompson was part of the Hundred Days Men enlistment program near the end of the Civil War. He mustered out in Peoria, Illinois on October 28, 1864 as a 1st Lieutenant.