Walter Washington De Lacy was born on February 22, 1819 at Petersburg, Virginia, United States. His father, William De Lacy, was of distinguished Irish family, claiming descent from Hugh de Lacy, one of the conquerors of Ireland in the twelfth century. His mother, Eliza, was the daughter of William Charles Lee, long British vice-consul at Oporto, Portugal.
Walter De Lacy’s parents died when he was quite young and he was brought up and given his early education by two maiden aunts.
In 1834 he was sent to St. Mary’s Catholic College in northern Maryland where he remained four years, engaged chiefly in the study of mathematics and languages.
During this time he secured the promise of an appointment at West Point, but in some way the promise failed of fulfilment.
There was at West Point an eminent mathematician and engineer, Prof. Mahan, who felt under obligations to De Lacy’s family, and he offered to give Walter private lessons in mathematics and engineering free of charge.
De Lacy began work as a construction engineer for the Illinois Central and Iron Mountain railways.
In 1840 he became assistant professor of French at West Point and later taught foreign languages to midshipmen in the navy. In 1846 he was employed by a syndicate to search for abandoned mines in Texas. While he was there the Mexican War broke out, and he volunteered and served throughout the war. Afterward, he was engaged in railroad work, helping survey the thirty-second parallel from San Antonio to San Diego. In 1855 he was in the Puget Sound country and served with distinction in the Nez Perce War. In 1858 De Lacy joined the party of Lieut. John Mullan, who was building the “Mullan Road” from Fort Benton to Walla Walla. He was placed in charge of construction from Sohon Pass to the Bitterroot River. He was also directed to make a map and report of the Bitterroot country. In 1860 he had finished this task and in 1861 became a prospector for gold in what is now Montana. He did not have much success and engaged for a time in packing from Walla Walla to the gold-mines. In 1863 he led a goldseeking party into the Snake River country and discovered Shoshone Lake and the Lower Geyser Basin of the Yellowstone Park. The first legislature of Montana (1864 - 65) employed him to make the first map of Montana; and it long remained the best. From then on, he was engaged in surveying. He located the initial point for public surveys in Montana and did much work in surveying and locating the line of the Northern Pacific. The last few years of his life he was employed in the surveyor general’s office in Helena, Mont. “Col. De Lacy, ” as he was popularly called, always remained a bachelor.
He was one of the founders of the Montana Society of Engineers and of the Montana Historical Society.
Walter Washington de Lacy was regarded as a genial and charming companion and had many friends. He was a brilliant talker and a noted teller of humorous stories and tales of adventure.
