Namesakes
Canadian Prime Ministers:
1 prime minister
John Abbott (a.k.a. Caldwell) 1891-1892 
Notable Politicians and Statespeople:
1 politician
John C. Calhoun (a.k.a. Caldwell) 1782-1850
Olympic Medalists:
1 gold
(gold) Caldwell Esselstyn 1956 rowing