 With legislative approval, voters in that territory voted to become part of Fremont County in 1896, finalizing the southern and eastern boundary.At Lemhi's creation, the western boundary was a line drawn from the Bitterroot Mountains to the southern line of Idaho County.The boundary was moved westward to the divide between the Payette and Salmon Rivers in 1873, moved eastward to a line drawn through the confluence of the Middle Fork and main Salmon rivers in 1885, and then mistakenly extended to the northern line of Idaho County in 1903 before being finalized at its present location in 1911.