Records of 19th-century homeopathic societies including the Homeopathic Institute of Philadelphia, American Provers' Union, Hahnemann Society of Northampton, and the Philadelphia Postgraduate School of Homeopathics. The Homeopathic Institute of Philadelphia appears to be the Philadelphia branch of the American Institute of Homeopathy. The American Institute of Homeopathy was founded in 1844 as a response to the death of homeopathy’s pioneer, Samuel Hahnemann. The Philadelphia branch was founded two years later in 1846, however, the American Institute of Homeopathy was already largely centered in Philadelphia, and held its annual conventions in the city until 1847. The American Institute of Homeopathy still exists today [2020]. The American Prover’ Union was a homeopathic group founded by Dr. Constantine Hering and 10 other homeopathic physicians in 1853 at Dr. Hering’s home in Philadelphia, Pennsylvania. The purpose of the American Provers’ Union was to track global developments in homeopathic remedies, and to test the effects and outcomes of these remedies. The American Provers’ Union was largely inactive after 1859. The Hahnemann Society of Northampton, which was officially known as the Homeopathic Society of Northampton and Adjoining Counties, was an early American homeopathic society founded in 1834 founded by several early American homeopathic physicians in Northampton, Pennsylvania to teach, spread and popularize the practice of homeopathy, which was largely new and unknown in America at that time. The Philadelphia Postgraduate School of Homeopathics was a small homeopathic college in Philadelphia that was opened in 1890. The main administrator and dean of the school was Dr. James Tyler Kent, a prominent homeopathic physician who practiced in St. Louis, Missouri before relocating to Philadelphia, Pennsylvania in 1888. The Philadelphia Postgraduate School of Homeopathics lasted only ten years and dissolved in 1900 after Dr. Kent resigned for a position in Chicago. Collection includes constituions and bylaws, meeting minutes, member list, and history on the homeopathic societies.