Henry Larcom Abbot (August 13, 1831 – October 1, 1927) was a military engineer and career officer in the United States Army.

He served in the Union Army during the American Civil War and was appointed brevet brigadier general of volunteers for his contributions in engineering and artillery.

Abbot attended West Point[6] and graduated second in his class, which included Jeb Stuart and G. W. Custis Lee with a degree in military engineering in 1854.

[7] In 1855, Abbot was assigned to work with Lieutenant Robert Williamson's Pacific Railroad Survey in California and Oregon.

[2] While serving in the Army, Abbot and Captain Andrew Humphreys conducted several scientific studies of the Mississippi River.

Regardless, it influenced the evolution of hydrology and was instrumental in the establishment of a United States Army Engineer School at Fort Totten in New York City.

[8] At the outbreak of the Civil War, Abbot was assigned to Brigadier General Irvin McDowell's forces and was wounded at the First Battle of Bull Run.

[7] On January 19, 1863, he was appointed colonel of the 1st Connecticut Heavy Artillery but on March 3, 1863, was transferred to the Washington Defenses, where he commanded a brigade.

[7] He was appointed to the Board of Consulting Engineers by Theodore Roosevelt and served between 1905 and 1906 after the Americans took control of building the canal.