1963 — The fourth and current American Chiropractic Association (ACA) was formed in 1963 by a merger of the National Chiropractic Association and the International Chiropractic Association.

Three previous organizations had used the name American Chiropractic Association (see 1922 and 1930).

It provides lobbying, public relations, professional and educational opportunities for doctors of chiropractic, funds research regarding chiropractic and health issues, and offers leadership for the advancement of the profession.

Based in Arlington, Va., the ACA is the largest professional association in the world representing doctors of chiropractic.