Benjamin Banneker (November 9, 1731 – October 19, 1806) was a free African-American almanac author, surveyor, landowner and farmer who had knowledge of mathematics and natural history. Born in Baltimore County, Maryland, to a free African-American woman and a former slave, Banneker had little or no formal education and was largely self-taught. He became known for assisting Major Andrew Ellicott in a survey that established the original borders of the District of Columbia, the federal capital district of the United States.
Banneker's knowledge of astronomy helped him author a commercially successful series of almanacs. As early as 1788, Banneker began to make astronomical calculations, and he accurately predicted a solar eclipse that occurred in 1789. In 1791, while working with Andrew Ellicott and others in surveying the land that would become Washington, D.C., Banneker made other astronomical observations. He corresponded with Thomas Jefferson on the topics of slavery and racial equality, Jefferson having earlier drafted the United States Declaration of Independence. Abolitionists and advocates of racial equality promoted and praised Banneker's works.