Caleb Atwater (December 23, 1778 – March 13, 1867) was an American politician, historian, and early archaeologist in the state of Ohio. He served several terms as a state politician and was appointed as United States postmaster of Circleville, Ohio. He was known best during the 19th century for his publication History of the State of Ohio (1838), the first book-length history of the new state. It also included much natural lore.
Atwater was recognized by contemporaries as a pioneer of the study of the mounds or massive earthworks in the Ohio Valley; he published an account during 1820. These are now known to have been constructed by ancient Native Americans of the United States. At the time, Atwater and other scholars developed various theories of origin; he thought a culture other than ancestors of Native Americans created such monuments. He helped publicize a theory by John D. Clifford, an amateur of Lexington, Kentucky, who suggested that people related to Hindus of India had migrated by sea and built the mounds, to be replaced by ancestors of contemporary Native Americans.
Caleb Atwater was born in North Adams, Massachusetts during 1778 during the American Revolutionary War. He was the son of a carpenter and his wife, and educated at local schools. He graduated from Williams College. After failing as a schoolmaster in New York City, he studied theology and became a Presbyterian minister. His first wife Diana Lawrence died after the birth of their first child.
Dissatisfied with the ministry, the widower Atwater studied law, studying and working with a judge in Marcellus, New York. He was admitted to the state bar. Instead of practicing, he entered into business and soon became bankrupt.
As a result of this failure, during 1815 he moved with his new wife (Belinda Butler) to Circleville in Ohio, founded during 1810. They had nine children together.