David D. MacMillan

David D. MacMillan (born November 1, 1954) is an American heir. He is the son of John Hugh MacMillan.

He is a member of the Cargill family and member of the Cargill board of directors. He was also on the board of directors of Waycrosse Inc, Cargill's investment arm. He graduated from New England College in 1978.

He and his wife Karen are donors to numerous organizations, including Higher Ground, the Greater Twin Cities United Way, drugfree.org, Central Institute for the Deaf, Groves Academy, the Minnesota Zoo, the Buffalo Bill Historical Center, and the SwiftSure Ranch.