Idaho is the only state that was possibly named as the result of a hoax (the so-called "Idahoax") although this is disputed. The exact origin of the name remains a mystery. In the early 1860s, when the United States Congress was considering organizing a new territory in the Rocky Mountains, eccentric lobbyist George M. Willing suggested the name "Idaho," which he claimed was derived from a Shoshone language term meaning "the sun comes from the mountains" or "gem of the mountains." Willing later claimed that he had made up the name himself.Congress ultimately decided to name the area Colorado Territory when it was created in February 1861.
However, the name "Idaho" did not go away. The same year Congress created Colorado Territory, a county called Idaho County was created in eastern Washington Territory. The county was named after a steamship named Idaho, which was launched on the Columbia River in 1860. It is unclear whether the steamship was named before or after Willing's claim was revealed. Regardless, a portion of Washington Territory, including Idaho County, was used to create Idaho Territory in 1863.

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