How you cite a map depends on where you find it. However, below are several ways to cite maps depending on where you found them.
1. A single sheet map
Basic form: Author. Title. Edition. Scale. Place of publication: Publisher, Date.
Example: U.S. Central Intelligence Agency. Madagascar. 1:3,465,000. [Washington, D.C.]: Central Intelligence Agency, 1973.
2. Map in a book
Basic form: Map author. Map title. Scale. Place of publication: Publisher, Date. In: Book author. Book title. Edition. Place of publication: Publisher, Date, page.
Example: Fig. 5: Major Seaports and Transportation Axes in Southern and South Central Africa (1978). 1.6 cm. = 500 km. In: Wiese, Bernd. Seaports and Port Cities of Southern Africa. Wiesbaden: Franz Steiner Verlag GmbH., 1981, p. 23.
3. Map in a periodical article
Basic form: Map author. Map title. Scale. In: Article author. "Article title," Journal title, Volume (Date): page.
Example: U.S. Geological Survey of the Territories. Yellowstone National Park; From Surveys Made Under the Direction of F. V. Hayden, U.S. Geologist and Other Authorities, 1871. Scale not given. In: Walsh, Jim. "Exploration and Mapping of Yellowstone National Park," Meridian, 3 (1990): 14.
4. Satellite imagery
Basic form: Author. Title or Scene ID, Satellite and sensor name (as appropriate). Scale. Place of publication: Publisher, Date of image collection (NOT date of reproduction).
Example: U.S. National Aeronautics and Space Administration. [Santa Barbara Region, California] E-2 429-17512-4, 5, 7, Landsat 2. 1:500,000. Sioux Falls, S. Dak.: EROS Data Center, 1976.
5. Map in a series - National topgraphic series
Basic form: Author. Sheet title from the series. Edition. Scale. Series, number. Place of publication: Publisher, Date.
Example: Canada. Surveys and Mapping Branch. Goose Bay, Newfoundland. Canada 1:250,000, Sheet 13F. Ottawa, Canada: Surveys and Mapping Branch, 1965.
All of the examples are from Cartographic citations: a style guide. 2nd ed. (2010).
These citation examples help when you need to cite original maps created in software or online.
1. Mapping software
Basic form: Author. Title. Edition. Place of production: Producer, Date of copyright or production.
Example: GeoLytics Inc. CensusCD Neighborhood Change Database (NCDB) 1970-2000 Tract Data: Selected Variables for US Census Tracts for 1970, 1980, 1990, 2000 and Mapping Tool. E. Brunswick, NJ: GeoLytics, 2003.
2. Geospatial data
Basic form: Author. Title. Edition. Place of production: Producer, Date of copyright or production.
Example: U.S. Bureau of the Census. Streets on a Disk, Accessory File, Santa Barbara County, California. Simi Valley, Calif.: Klynas Engineering, [198?].
3. Map (static) from Website
Basic form: Author. Map title. Scale. "Title of website" <URL> (date accessed).
Example: Sanborn Map Company. Andover 1923. Scale not given. "Sanborn Fire Insurance Maps: New Hampshire towns, 1880s-1940s".<https://libarchive.dartmouth.edu/cdm4/browse.php?CISOROOT=/sanborn> (Accessed April 14, 2011).
4. Interactive map created from website
Basic form: Author. Title of map created. Layers used. Scale. Name of person who generated map; using "Title of Website" <URL> (date accessed).
Example: Harvard University. Language Families of Western Africa. Layers used: 2001 Boundaries. Scale unknown. Map generated by Frank Johnson; using "AfricaMap" <http://cga-3.hmdc.harvard.edu/africamap/> (Accessed June 20, 2009).
5. Manuscript maps - Early and modern maps
Basic form: Author. Title. Scale. Date. Collection, records or papers to which the manuscript belongs. Name of repository, Location. Library reference designation.
Example: Tanner, Benjamin. "State of New Hampshire." Scale ca. 1:700,000. Evans Map Room Special Collection. Evans Map Room, Baker/Berry Library, Dartmouth College. G3740 1796 .T366.
All of the examples are from Cartographic citations: a style guide. 2nd ed. (2010).