Common Ground USA is a 501c4 registered charity, established in 1984 to promote the philosophy of Henry George and its implementation. It's mission statement:
"Common Ground-U.S.A. is dedicated to the principle that all persons have equal and common rights in the earth and its resources and each individual has an exclusive right to the income from his or her own labor and capital investment. We are also dedicated to support and improve the free market, including purchase, ownership, and sale of real estate.
"Therefore, we are committed to reducing and replacing taxes on labor and capital. We propose to pay for essential government services by adequate taxation of the value of land and other natural resources. We also propose fees for pollution, resource extraction, and use of the public commons. We believe these changes will increase total wealth and equality of opportunity, thereby improving the quality of life for all individuals and the functioning of government."
Right now, there are 7 active chapters in North America (really the U.S. though there used to be one in Canada). CGUSA is one of the older and more established Georgist activist groups and has long and deep roots in the Georgist community.
It publishes a bi-monthly newsletter, reaches out to politicians and seeks to implement related laws and policies (as a c4, not a c3, organization, we can go where c3s cannot in terms of direct support). The chapters are semi-autonomous (I am president of the NY chapter since 2010 and this is our local website: http://commongroundnyc.org/) and localized in their membership and focus. The national board meets as necessary and always annually just before the annual Council of Georgist Organizations meeting held a various locations in the U.S.
CGUSA has successfully promoted laws and policies over the years, and worked with other Georgists to advance the cause.
Review from Guidestar