US civil engineer who designed the first wire-cable suspension bridge in the US, in 1842. He also designed the world's first long-span wire-cable suspension bridge, crossing the Ohio River at Wheeling, West Virginia.
Ellet was born in Pennsylvania and began his career as a surveyor and assistant engineer on the Chesapeake and Ohio Canal 1828. In 1831–32 he was in Europe, enrolled at the Ecole Polytechnique in Paris and studied the various engineering works taking place in France, Germany, and Britain.
For his first wire-cable suspension bridge, over the Schuylkill River at Fairmount, Pennsylvania, Ellet introduced a technique he had learned in France of binding small wires together to make the cables.
The central span of the suspension bridge over the Ohio River was at 308 m/1,010 ft the longest ever built when completed 1849. The bridge failed under wind forces in 1854; however, Ellet's towers remained standing and the bridge was rebuilt.
Following the outbreak of the Civil War in 1861, Ellet produced a steam-powered ship for the Union forces to ram the Confederates on the Mississippi River. In June 1862, Ellet led a fleet of nine of these rams in the Battle of Memphis. The Union side was victorious, but in the course of the fighting Ellet was fatally wounded.