The AAS has five divisions - the Division for Planetary Sciences (1968), the Division on Dynamical Astronomy (1969), the High Energy Astrophysics Division (1969), the Solar Physics Division (1969) and the Historical Astronomy Division (1980).
The group was founded in 1899 by the efforts of George Ellery Hale. The constitution of the group was written by Hale, George Comstock, Edward Morley, Simon Newcomb and Edward Pickering. These men plus four others were the first Executive Council of the society, Newcomb was the first president. The initial membership was 114. The AAS name of the society was not finally decided until 1915, previously it was the Society the Astronomical and Astrophysical Society of America.