34th meridian west from Washington

The meridian was first used as a boundary when the Montana Territory was created in 1864. It served as Montana Territory's extreme southwestern boundary.^[2] The next usage of the boundary came when the Wyoming Territory was established in 1868, with the meridian as its western boundary.^[3] It was also at this time that it became much of the then-Idaho Territory's eastern boundary, as well as the extreme northeastern boundary of the then-Utah Territory. Montana became a state in 1889, with Idaho and Wyoming following the year afterwards.^[4][5][6] Utah became a state in 1896.^[7]

In the present day, the meridian is used as Wyoming's western border with Montana, Idaho and Utah.