“I put down what I considered the best”: Walter W. de Lacy’s Mapping of Montana

by Molly Kruckenberg, Research Center Director

In February of 1865 the first Territorial Legislative Assembly approved the payment of $625 to Walter W. de Lacy for creating a map of the Territory of Montana, “for the use of the Governor and the Legislative Assembly.”  The map that de Lacy created (shown below) is the first map of what is now the State of Montana; the original of that map is in the collections at the Montana Historical Society.


Walter W. de Lacy's Map of the territory of Montana, with portions of the adjoining territories : showing the gulch or placer diggings actually worked and districts where quartz (gold & silver) lodes have been discovered up to January 1865 [See map on Montana Memory Project].

Walter W. de Lacy was a bachelor, traveling across much of the country during the 73 years of his life.  Born in 1819 in Petersburg, Virginia, de Lacy was educated as a civil engineer by West Point professors.  His first engineering jobs as part of railroad surveys, took him west to Illinois and Missouri.  After a few years as a language and mathematics professor with the U.S. Navy, de Lacy joined the first of several exploratory expeditions in the southwest, for the purpose of determining the viability of road construction, military fort placement and railroad engineering.

By the mid-1850s de Lacy had made his way to the Pacific Northwest, working on similar surveying assignments.  In 1859 he was attached to the command of Lt. John Mullan to survey and build a road from Fort Benton to Walla Walla; this was de Lacy’s first venture into what would become Montana Territory.

de Lacy’s most well-known accomplishment was the completion of the first map of the new territory of Montana in 1865.  But he was instrumental in many early mapping and surveying endeavors in Montana.  He created a map of Oro Fino and Grizzly Gulches near Helena, in 1865, as well as laying out the townsites of Deer Lodge and Argenta in the same year and Fort Benton in 1864.  And, with B. F. Marsh, he located the initial point for public survey in the Territory.

Map of Oro Fino and Grizzly Gulches near Helena City, Edgerton County, Montana Territory [See map on Montana Memory Project].

After serving in the Sioux War in 1867, de Lacy retired from military service and spent the remainder of his life in public service.  He worked as an engineer for the city of Helena from 1872-1886, serving as the City Engineer from 1883-1884.  From 1886 until his death in 1892, de Lacy worked for the U.S. Surveyor General’s Office in Helena.  He was a founding member of the Montana Society of Civil Engineers and the Montana Historical Society.

Walter de Lacy’s maps are both significant parts of Montana’s history, telling much about the early development of the Territory, as well as being works of art in their own right.  Much of de Lacy’s work is documented in the collections of the MHS, through nearly 20 maps authored by de Lacy as well as a small collection of his personal papers (see the guide to the collection of personal papers).