The American Public Health Association (APHA) is a Washington, D.C.-based professional organization for public health professionals in the United States. Founded in 1872 by a group of physicians, including Dr. Stephen Smith and Dr. Henry Hartshorne, APHA has more than 25,000 members worldwide. The Associations defines itself as: "APHA champions the health of all people and all communities. We Strengthen the public health profession. We speak out for public health issues and policies backed by science. We are the only organization that influences federal policy, has a 140-plus year perspective and brings together members from all fields of public health." It defines its mission as: "Improve the health of the public and achieve equity in health status."