Elijah Johnson (c.1789 – April 3, 1849) was an African American who was one of the first colonial agents of the American Colonization Society in what later became Liberia. He was probably born in New Jersey, received some limited schooling in New Jersey and New York, served as a soldier in the War of 1812 and studied for the Methodist ministry. He had two children out of wedlock, Lewis Johnson (1810 – 1838) and Charles Johnson (born 1812). He later married and had one daughter, Elizabeth (born 1818), with his wife Mary Johnson.
Elijah Johnson was of mixed raced ancestry, and was born about 1790 probably in New York. Two of his children that are seldom mentioned are Sarah (b. about 1811), and Elijah Johnson Junior (born about 1812). Sarah and her brother Elijah were left in an orphanage in Chester County in 1816. There was no mention of their mother's identity, but the father was listed as Elijah Johnson. He came into Pennsylvania from New York, prior to the War of 1812, in which he served. After the War, he studied at a Methodist school and was ordained as a minister of the Methodist church in northern New York. He is probably a descendant of Molly Brant, a Mohawk woman, and her white husband William Johnson.
Elijah Senior was a member of the American Colonization Society as was his friend Jehudi Ashmun. They traveled to Liberia on the same ship in 1820 along with their wives and children. on the ship Elizabeth and, on March 9, 1820, landed on Sherbro Island in what is today Sierra Leone. The settlers had difficulty surviving, with many (including his wife Mary) dying from Malaria and yellow fever. In 1821, the surviving settlers moved to Providence Island near what is today Monrovia. There, Johnson married Rachel Wright (born ca. 1798) with whom he had several additional children including Hilary R. W. Johnson, who would become the eleventh President of Liberia in 1884.