The name Montana comes from the Spanish word Montaña meaning "mountain" or more broadly, "mountainous country". Montaña del Norte was the name given by early Spanish explorers to describe the entire mountainous region of the west. Historians believe General and former Kansas Territory Governor James W. Denver was aware of this when asked by Senate chairman of the Committee on Territories Stephen A. Douglas for a name of one of the several territories he was planning on proposing. Though Douglas never did introduce a bill with the name Montana, he is credited with at least introducing the name. The name was eventually added to a bill by the United States House Committee on Territories, which was chaired at the time by Rep. James Ashley of Ohio, for the territory that would become Idaho Territory.
The name was successfully changed by Representatives Henry Wilson and Benjamin F. Harding both complained that Montana had "no meaning". When Ashley presented a bill to establish a temporary government in 1864, for a new territory to be carved out of Idaho, he again chose Montana Territory. This time Rep. Samuel Cox, also of Ohio, objected to the name. He complained that the name was a misnomer given that most of the territory was not at all mountainous and that an Indian name would be more appropriate than a Spanish one. To this Rep. Elihu Washburne of Illinois jokingly suggested Abyssinia. Cox suggested Shoshone, but its translated meaning of "snake" elicited laughter and a remark that the bill had progressed too far to have the territory's name changed without unanimous consent.
Cox then suggested that the new territory be called 'Jefferson', to which Ashley responded, "Oh, well, we are opposed to that." This astounded Cox, "Opposed to Jefferson! I propose that we name the new territory, by unanimous consent, 'Douglas Territory.' I think the gentleman opposite will agree to that," to which Ashley replied, "Oh, no, we cannot do that." Rep. John Pruyn then commented that the Governor Lyon of Idaho Territory said he thought the names for the two territories should be reversed given Idaho was more mountainous than Montana. Finally, Rep. Edwin Webster of Maryland stepped in and suggested that every father has the right to name his own child, and since the bill was the progeny of the Committee on Territories, the committee could name it whatever they wanted. After more laughter the name was settled.