James Buchanan Eads (23 May, 1820–8 March, 1887) was a American engineer and inventor.

Eads was born in Lawrenceburg, Indiana, and named for his Mother's cousin, then Congressman and subsequent President of the United States James Buchanan. His early life was spent growing up in St. Louis, Missouri.

Eads made his initial fortune in salvage, by creating a diving bell for retrieving goods from the bottom of rivers that were sunk there by riverboat disasters, especially along the busy Mississippi River. He also devised special boats for raising the remains of sunken ships from the river bed.

In 1861, after the outbreak of the American Civil War he was contracted to construct ironclads for the United States Navy, and impressed the Navy by producing 8 such ships within 100 days. He continued to produce ironclad steamships throughout the war, which greatly aided the Union.

Eads designed and built the first bridge to cross the Mississippi River, the famous Eads Bridge at Saint Louis, Missouri, constructed from 1867 thorugh 1874.

The Mississippi in the 100-mile-plus strech between the port of New Orleans, Louisiana and the Gulf of Mexico frequently suffered from silting up of its outlets, stranding ships or making parts of the river unnavigable for a period of time. Eads solved the problem with a wooden jetty system that narrowed the main outlet of the river, which caused the river to cut its channel deeper and allowing year-round navigation.

He designed a gigantic railway system intended for construction at the Isthmus of Tehuantepec, which would carry ocean going ships across the isthmus from the Gulf of Mexico to the Pacific Ocean; this attracted some interest but was never constructed.

In 1884 he became the first US citizen awaded the Albert Medal of the Society of the Arts.

Eads died in Nassau, Bahamas on 8 March, 1887.