The First Capital
The organization of Idaho Territory was proclaimed in Lewiston July 10, 1863
and the first two legislatures met here.
When Lewiston served as the capital, Idaho Territory included modern
Montana and practically all of Wyoming--an area much larger than Texas.
Then in 1864, after Montana was established as a separate territory and most of
Wyoming was attached to Dakota, the governor and legislature decided to locate
the capital Idaho in Boise, where it has been ever since. ~ text of marker