Center For Inquiry (US) - http://www.centerforinquiry.net/
CFI is the US sister-organization for Centre for Inquiry Canada. It acts to promote reason, science and secularism in the US.
International Humanist and Ethical Union – http://iheu.org/
James Randi Education Foundation – http://www.randi.org/site/
The James Randi Educational Foundation is an educational charity which works to help people defend themselves from paranormal and pseudoscientific claims.
Atheist Alliance International – http://www.atheistalliance.org/
Atheist Alliance International (AAI) is a global federation of atheist and freethought groups and individuals committed to educating its members and the public about atheism, secularism and related issues.
Humanist Canada – http://humanistcanada.ca/
Humanist Canada works to promote the separation of religion from public policy and foster the development of reason, compassion and critical thinking for all Canadians through secular education and community support.