What is Lost Dakota?
Lost Dakota was an 11mi2 (28 km2) piece of unassigned land left over after Congress cut Montana and Wyoming from the Idaho Territory in 1864. The territory was located near present-day West Yellowstone, Montana. Congress overlooked it while dividing up the Idaho Territory, and it remained unassigned for nine years.
During its existence, it remained an ungoverned, uninhabited land, home to grizzly bears, elk, deer, pronghorn, and other wildlife of the region.
How did Lost Dakota become a territory?
The area of present-day southwest Montana and eastern Idaho started experiencing rapid population and economic growth in 1862. Around this time, local miners began petitioning Congress to create their own territory.
Congress obliged, creating the Idaho Territory in 1863. However, the Idaho Territory encompassed an enormous swath of land, covering all of present-day Idaho and Montana and most of Wyoming.
The territory was split down the middle by the Rocky Mountains. With its administrative center located in the far east town of Lewiston, the territorial governing body struggled to properly manage its land and communities east of the Rocky Mountains.
In 1864, at the request of miners located in Bannack and other mining towns east of the Rockies, Congress decided to carve the Montana Territory from the Idaho Territory, giving this region its own governance.
The initial proposal for Montana’s boundaries created some problems. The proposal created an impractically shaped Dakota Territory, which included a rectangular shape south of Montana. To resolve the issue, Congress created Wyoming from the rectangular shape.
In doing so, they overlooked an 11 mile2 (28 km2) piece of Dakota Territory between Montana and Idaho (see above map) and forgot about it for nine years.
Nine years of Lost Dakota
This small piece of land, 360 miles (580 km) from its governing Dakota Territory, informally became known as ‘Lost Dakota’ and remained an exclave for nine years before Congress gave it to Montana in 1873.
Lost Dakota map
To help you visualize where Lost Dakota was located, imagine drawing a horizontal line from Wyoming to Idaho just above West Yellowstone in southwest Montana, as depicted in the map below:
Why didn’t they just incorporate Lost Dakota into one of the surrounding states from the start?
Due to faulty maps and surveys, Lost Dakota was wiped from public view, and the federal government forgot about it for most of its existence.
Who lived in Lost Dakota?
No people inhabited Lost Dakota during its existence. It was wild, home to various wildlife, including grizzly bears, moose, elk, and pronghorn.
When Lost Dakota was created, Montana was located in a remote region of the country, accessible only by steamboat up the Missouri River, by horseback, or on foot. Many regions of Montana and the surrounding area were completely uninhabited.
Today, Lost Dakota is a part of Montana. It remains mostly undeveloped, with few streets or even footpaths crossing the area, and it is densely populated with grizzly bears.
