Butte, America’s Story Episode 264 - The Idaho-Montana Boundary

Welcome to Butte, America’s Story. I’m your host, Dick Gibson.

On May 26, 1864, Abraham Lincoln signed the act passed by Congress separating the Territory of Montana from the Territory of Idaho.

For political and financial reasons, not to mention geographic convenience, pioneers in Butte rode up to the Continental Divide and convinced the surveyors defining the boundary that the divide ran west and north from Lost Trail Pass rather than east to the low summit south of Butte, through the Highland Mountains, and up the East Ridge. Consequently, Butte became part of Montana rather than staying with Idaho.

It’s a common tale, but there isn’t a shred of truth to it. No one convinced the surveyors anything, and they weren’t lost, or drunk, or distracted by gold fever. The surveyors didn’t come to Butte to be waylaid in a brothel. There actually weren’t any surveyors.

The boundary between Montana and Idaho Territories was defined in the original acts describing the two areas, and with one tiny exception, it always was exactly as it is now. But even though it was defined in 1864, it was not surveyed until 1904 to 1906, so the Territories and later States actually got along without a fully surveyed boundary for 40 years. Howard B. Carpenter led a team through the mountains for three summers in the 19-zeros, placing mileposts every mile and cairns every quarter mile for the 650-mile length of the border between Montana and Idaho.

When the boundaries of Idaho and Montana Territories were defined in their separate organic acts, the borders were identical to each other except where they run into the western edge of Wyoming. There, the Idaho border followed the divide to the Wyoming line, but the Montana border came down from the north to 44º 30’ north latitude, and then went west to the divide, a distance of just a few miles. That left a tiny 11-square-mile wedge of land that was technically unassigned to either Montana or Idaho, so it remained part of Dakota Territory by default. Idaho Territory had been carved out of Dakota, and Montana came out of Idaho, so any undefined country would still be Dakota.

The situation was remedied by statute in 1873, and “Lost Dakota” became the southern tip of Gallatin County, Montana, but pre-1873 maps exist that show a small zone there as “Part of Dakota.” Some showed a much larger area than really was in play because the geography of the divide was unknown. Butte was typically not shown on maps from 1871-74 because it was fast becoming a ghost town, with a population ranging from about 60 to about 250. It took the discovery of hidden silver in 1875 to rejuvenate Butte’s busted mining camp.

As writer Edwin Dobb has said, "Like Concord, Gettysburg, and Wounded Knee, Butte is one of the places America came from." Join us next time for more of Butte, America’s Story.