The Association of Religion Data Archives (ARDA) currently archives over 400 local, national, and international data files, and offers a wide range of research tools to build surveys, preview data on-line, develop customized maps and reports of U.S. church membership, and examine religion differences across nations and regions of the world. The ARDA also supports reference and teaching tools that draw on the rich data archive. This research note offers a brief introduction to the quantitative data available for exploration or download, and a few of the website features most useful for research and teaching. Supported by the Lilly Endowment, the John Templeton Foundation, the Pennsylvania State University, and the Baylor Institute for Studies of Religion, all data downloads and online services are free of charge.