RRCHNM20 is a collection of material about projects created by the Roy Rosenzweig Center for History and New Media at George Mason University in the first twenty years of its existence, 1994-2014. It aims to offer insight on the process of creating digital history, and to highlight the roles of a range of staff and collaborators, across twenty years of changing structures, practices, concerns, hardware, and software. The collection includes 67 of the 149 projects undertaken by the Center, as of November 2014. Most of the documents are grant proposals and reports. The site also includes information on the just over 150 people who worked at the Center during its first twenty years. After the site launch, DH Fellows created exhibits on the history of nine projects.

The site was created by Jannelle Legg, Anne McDivitt, and Amanda Regan, with guidance from Sheila Brennan. Additional content was added by Jannelle Legg, Debra Kathman and Lara Harmon.