A searchable version of the most recent edition of the Chicago Manual of Style. A Citation Quick Guide provides common examples for formatting citations.
Examples from the Library of Congress on how to cite manuscripts, maps, cartoons, newspapers, and other types of primary sources found on their website using Chicago style.
An excellent guide by Patrick Rael, Professor of History, Bowdoin College. Includes informative sections on historical arguments and crafting a thesis, among other topics.