Maps and Atlases: Citing Maps (online), North Carolina State University. Formats and sample citations for print and online maps. Format is adapted from Cartographic Citations: A Style Guide, which follows Chicago style.
Cartographic Citations: A Style Guide(print). Assistance in citing cartographic materials of all formats in Chicago style. The most thorough citation guide to maps printed in periodicals and books, cross sections, facsimiles, relief models, globes, and aerial photographs. Section on electronic spatial data includes entries for GIS data, real-time online maps, and interactive online maps.
MLA, 8th edition
Citing Maps (online), Western Washington University. Examples of citations for print and online maps. Note: the APA examples on this page are not from the current edition.