The world’s largest animal advocacy group, the Humane Society of the United States (HSUS), is head quartered in Washington D.C. with over 500 employees and field representatives in 35 states. The HSUS works closely with its international organization, Humane Society International (HIS). Latest figures available indicates that HSUS had a membership of 10.5 million in 2008 which is way more than the membership of 7.4 million that it had five years ago. As of 2008, it had funds totaling $160 million. It publishes the bi-monthly Animal Sheltering magazine. It operates the Humane Society Veterinary Medical Association, a free veterinary service for animals in poor areas.

The HSUS was founded in 1954 to address cruelties to animal and to resolve animal welfare problems beyond the local capabilities. It operates animal sanctuaries in five states. It does not run local shelters or run any local animal care and control establishments. Instead it is currently focusing on national issues such as “puppy Mills”, tighter legislation on dogfighting and cockfighting, factory farming, fur trade and wildlife abuses.

Twenty-eight states in the U.S. are considering tighter legislation on dogfighting and cockfighting. Thirteen U.S. states are considering legislation on “puppy mills” and mass dog breeding.