The Land Unknown is a 1957 science fiction CinemaScope adventure film about a naval expedition trapped in an Antarctic jungle. The story was allegedly inspired by the discovery of unusually warm water in Antarctica in 1947. It stars Jock Mahoney and Shirley Patterson and was directed by Virgil W. Vogel. The film's low-budget special effects include men in dinosaur suits, puppets and monitor lizards standing in for dinosaurs.

Jacques Joseph O'Mahoney, known professionally as Jock Mahoney, was an American actor and stuntman. He starred in two Action/Adventure television series, The Range Rider and Yancy Derringer. He played Tarzan in two feature films and was associated in various capacities with several other Tarzan productions. He was credited variously as Jacques O'Mahoney, Jock O'Mahoney, Jack Mahoney, and finally Jock Mahoney.