The proliferation of U.S. horror films in the 21 st century has engendered an increase in critical and academic response which has almost exclusively focused on the conventions of mainstream horror cinema. That is, films sanctioned by classificatory bodies, released through mid to large production companies and exhibited via selected to wide theatrical releases. While academic work, drawing from film and cultural studies, has provided a much needed engagement with the popularity and themes of contemporary U.S. horror they have tended to exclude marginal or ‘hidden’ hardcore horror film examples. Therefore, this article will provide an introductory account of the films that form part of this horror sub-genre, from Eric Stanze’s Scrapbook (2000) through Fred Vogel’s August Underground trilogy (2001 – 2007) to Stephen Biro’s American Guinea Pig: Bouquet of Guts and Gore (2014). The article will briefly map out the criteria for a definition of hardcore horror before discussing some of its key examples. It is not my intention to simply interpret the films but to look at their ‘archaeology’ to account for the production practices, marketing and distribution strategies, and film reception. The importance of looking at hardcore horror in terms of an archaeology is to reintegrate its marginal status and cultural practices so that a wider examination of the cultural field of U.S. horror in terms of how it is made and experienced can be advanced.