American Canyoneers - The USA's national organization promoting and preserving access to public and private canyonering areas/routes. Founded in 2012. Canyoneers SHOULD join and get involved as a responsibility to the community.
Zion Canyoneering Coalition - Worked with Zion National Park from 2000 to 2005 to promote canyon access and public participation in Zion's wilderness management policy-making process. Access work is now under the wing of American Canyoneers (above), but there is quite a bit of interesting background reading at the ZCC website.