Science & Technology

Benjamin Banneker

Born November 9, 1731 · Baltimore County, Maryland · Joined the Ancestors October 9, 1806

A self-taught astronomer, mathematician, and farmer who helped survey the layout of Washington, D.C. — Benjamin Banneker was one of the greatest minds of colonial America and challenged Thomas Jefferson's beliefs about Black intellectual inferiority.

Known For

Helped survey Washington, D.C.

Achievement

Built a wooden clock entirely from memory

Legacy

Challenged Jefferson on racial equality

Benjamin Banneker was born free in Baltimore County, Maryland, the grandson of an Englishwoman and an enslaved African. Largely self-taught, he demonstrated extraordinary intellectual gifts from an early age. At 22, he built a fully functioning wooden clock entirely from memory after studying a pocket watch — the clock kept accurate time for over 50 years.

Banneker taught himself astronomy using borrowed textbooks and instruments, accurately predicting a solar eclipse that European-trained scientists had gotten wrong. In 1791, he was appointed to the survey team that laid out the boundaries of Washington, D.C. under Major Andrew Ellicott.

That same year, he sent a copy of his almanac to Thomas Jefferson along with a letter challenging Jefferson's assertion in Notes on the State of Virginia that Black people were intellectually inferior. His almanac, published annually from 1792 to 1797, was widely acclaimed as proof of Black intellectual capability.