Pediocactus bradyi is a very rare species of cactus known by the common names Brady's pincushion cactus, Brady's hedgehog cactus, and Marble Canyon cactus. It is endemic to Arizona in the USA, where it is restricted to Marble Canyon in Coconino County, though its exact distribution is not generally advertised due to poaching concerns. It is limited to a specific type of soil, it has a small distribution, and the species is threatened by a number of human activities. This has been a federally listed endangered species of the United States since 1979.