John William De Forest (1826-1906), a United States soldier and writer of realistic fiction

Lee De Forest (1873-1961), an American inventor with over 300 patents to his credit

DeVry University, formerly called the DeForest Training School, a private, for profit university system in the United States

Calvert DeForest (1921-2007), a United States actor and comedian, best known for his appearances on David Letterman's shows

De Forest, Wisconsin, a village in Dane County, Wisconsin, United States along the Yahara River

Henry deForest, an United States railroad executive who served as chair for the Southern Pacific Railroad's board of directors