Old Baldy, also known as the Tower, is a hill located near the village of Lynch, in Boyd County, in the northern part of the state of Nebraska in the Midwestern United States. It was visited by the Lewis and Clark Expedition on their way up the Missouri River in 1804; nearby, they discovered a colony of prairie dogs, an animal previously unknown to scientists. For its connection with Lewis and Clark, and because it has little changed since their passage in 1804, the site was listed in the National Register of Historic Places in 2004.