Nonprofit Databases and Listings
A web database of all IRS-registered charitable nonprofits includes 990 forms from IRS-registered charitable nonprofits
Home of the National Center for Charitable Statistics
Maryland Secretary of State
Provides a variety of nonprofit links and resources as well as links to other state listings.
Information on the 450,000+ membership associations
Better Business Bureau - Wise Giving Alliance
Ratings of nonprofit organizations
The Johns Hopkins Third Sector Project
Links to the Center for Civil Society, the Comparative Nonprofit Sector Project, and the Nonprofit Employment bulletins.
Major survey on civic engagement in the US in collaboration with Robert Putnam
American Religion Data Archive
Links to major data sources on religion