Jackman's diaries, letters, and outstanding collections of memorabilia are held in various depositories across the country, such as the Amistad Research Center at Tulane University in New Orleans and Atlanta University (now Clark Atlanta University) in Atlanta, Georgia. At Cullen's death, Jackman requested that his collection in Georgia be renamed, from the Harold Jackman Collection to the Countee Cullen Memorial Collection, in honor of his friend. After Jackman died of cancer in 1961, the collection at Clark Atlanta University was renamed as the Cullen-Jackman Collection to honor them both.