Arthur Rusmiselle Miller Spaid was born on July 27, 1866 in Capon Springs, West Virginia, to John W. Spaid and his wife, Margaret Elizabeth Brill Spaid. Arthur Spaid was the eldest of six children, with two brothers and three sisters: Luther Lore "Boyd" Spaid (1868–1877), Elia May Spaid (1870–1911), Martha Evalona Spaid (1875–1921), William Pohe Spaid (1878–1885), and Eleanor "Nellie" Love Spaid (1881–1963). His great-great-grandfather, George Nicholas Spaid (né Spaht), originated from Kassel, Germany, and settled in Hampshire County along the Cacapon River in the late 18th century. Arthur Spaid and his siblings were raised by their parents on a small farm on Timber Ridge. His father was a shoemaker who was interested in literature and recorded local history in notebooks.
