The Lewis and Clark Expedition explored these hills on June 3 and 4, 1804. Cedar Island and Cedar Creek on the north shore of the Missouri River were especially mentioned in the original journals of the expedition, and the beauty of the bluffs beyond was also described. West of this point, a small creek flowed into the river from the south. The explorers named this stream Nightingale Creek because a bird they thought to be a nightingale sang near their camp throughout the night.