An engineer of rare talent, Stephen H. Long made substantial contributions to the improvement of river navigation, the design of bridges and steamboat engines, and the development of improved river craft. A New Hampshire native, Long began his career in the U.S. Corps of Topographical Engineers in 1814. He explored western rivers in 1819 and 1820 with the Western Engineer. Long examined the Ohio, Mississippi, and Missouri River and reported on navigation conditions and obstructions. In 1824, he constructed the first federal dam on the Ohio River.
Long patented a novel method of bracing and counterbracing wooden bridges in 1836. From 1842 to 1856, Long headed up the Corps Office of Western River Improvements. Following the enactment of the Rivers and Harbors Act of 1852, he started an intensive program for improving the waterways under his authority. Stephen Long was appointed Chief of Engineers in 1861, a position he held until his retirement.