Horatio Allen (1802-1889) was a noted civil engineer and inventor, who worked with the Delaware & Hudson Canal Company, the South Carolina Canal and Railroad Company, the Croton Aqueduct, and the New York & Erie Railroad. Allen was born in Schenectady, New York, on May 10, 1802. His father, Dr. Benjamin Allen, was then professor of mathematics and natural philosophy at Union College.

Horatio Allen graduated from Columbia College in 1823 with high honors in mathematics. Deciding upon a career in engineering, he spent a year on the Chesapeake & Delaware Canal. Around 1825 he joined the staff of the Delaware & Hudson Canal Company as a resident engineer. When the company decided to import locomotives for use on its connecting railroad, Allen was sent to England in 1828 to procure them. Four locomotives were contracted for, the first in the United States. One, the STOURBRIDGE LION, was tested at Honesdale, Pennsylvania, on August 9, 1829, and Allen had the distinction of being the first man to operate a locomotive in the western hemisphere. However, the locomotives proved to be too heavy for the track structure and were not used in revenue service.

Upon completion of the Delaware & Hudson, Allen accepted the position of chief engineer of the South Carolina Canal and Railroad Company, which was planning to build from Charleston to a point opposite Augusta, Georgia. Allen pushed to have the company adopt locomotive power, and under his direction the West Point Foundry in New York City built the BEST FRIEND OF CHARLESTON, the first locomotive produced for sale in America.

Allen remained in Charleston until 1835, after which he and his new bride, Mary M. Simons, travelled abroad for three years. On their return, they settled in New York City, where Allen was named principal assistant engineer of the Croton Aqueduct. He was also serving as a consulting engineer to the New York & Erie Railroad. In 1842 he became one of the proprietors of the Novelty Iron Works, a noted builder of marine engines. Allen retired from active business in 1870, but continued with consulting work. In his later years he devoted much time to education, particularly the teaching of astronomy, for which he wrote a textbook and constructed several instruments. He died on December 31, 1889 at South Orange, New Jersey.