C56 or C-56 may refer to: C-56 (Michigan county highway) , an Admirable-class minesweeper of the Mexican Navy Caldwell 56, a planetary nebula Hexachlorocyclopentadiene, an organochlorine compound JNR Class C56, a class of Japanese steam locomotive Lockheed C-56 Lodestar, an American military aircraft Ovarian cancer Sickness Insurance (Sea) Convention, 1936 of the International Labour Organization Two Knights Defense, a chess opening Affordable Housing and Groceries Act, Bill C-56