The Idaho Territory was established on March 4, 1863, as a region of the United States. It was created from parts of the Washington Territory and included areas that are now part of Montana and Wyoming. The territory was primarily inhabited by various Native American tribes, including the Shoshone and Nez Perce. Its capital was initially located in Lewiston. The Idaho Territory played a significant role in the westward expansion of the United States. It became a center for mining, agriculture, and settlement during the mid-19th century. In 1890, Idaho was admitted to the Union as the 43rd state, marking the end of its territorial status.