BLS Industry Report: Religious, Grantmaking, Civic, Professional, and Similar Organizations: NAICS 813
Chairty Navigator
Charity Watch
Idealist
ieCapaciteria
The National Center for Charitable Statistics (NCCS)
Philanthropedia
Top Nonprofits: Top 100
The Most Comprehensive Source of U.S. Nonprofit Tax Data
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IRS: SOI Tax Stats - Charities & Other Tax-Exempt Organizations Statistics
IRS: Stay Exempt
IRS: Tax Exempt Organization Search (formerly Select Check)
IRS: Tax Information for Charities & Other Non-Profits
CFDA: Home
Grants.gov
National Council of NonProfits: Tools and Resources
Up Counsel: Types of Nonprofits
USA.gov: Starting a nonprofit
Stand for Education
Bill & Melinda Gates Foundation
Teach for America
The Education Trust