Ingersoll Lockwood (August 2, 1841 – September 30, 1918) was an American lawyer and writer. As a writer, he is particularly known today for his Baron Trump children's novels. However, he wrote other children's novels, as well as the dystopian novel, 1900: or; The Last President, a play, and several non-fiction works. He wrote some of his non-fiction under the pseudonym Irwin Longman.