Farrer was born on 3 April 1845 in the town of Docker, Westmorland in the English north west (now Cumbria).
In 1882 Farrer married Henrietta Nina the only daughter of Leopold Fane de Salis, the then Member of Parliament for Queanbeyan, N.S.W. Four years later De Salis gifted to Nina alone, 97 hectares of land.