Henry Richmond Droop (September 12 1832 – March 21, 1884)* was an English mathematician. He is widely credited with devising the Droop quota that is used today in the common voting system known as the Single Transferable Vote. He also may have been the first to write down what later became known as Duverger's Law, in 1869.
He married Clara Baily (ca. 1841 - September 7 1921) on 17 August 1872* and was the father of John Percival Droop (1882 - 1963), the archaeologist.
- William H. Riker Duverger's Law: Forty Years Later. From Grofman and Lijphart Electoral Laws and their political consequences 1986.