Edwin Russell (E.R.) Jackman (February 14, 1894 – May 12, 1967) was an American agricultural expert from Oregon. He helped form the Oregon Seed Growers' League and the Oregon Wheat League. In 1964, he joined Reub Long to write The Oregon Desert, which is still a very popular book fifty years after its original publication. Jackman's professional papers and photograph collection are maintained in the Oregon State University archives.