MLA

General, United States. Surveyor. Map of a Part of Washington Territory : to Accompany the Report of the Surveyor General, 1860-61. s.n.], 1860. https://collections.library.yale.edu/catalog/15821631.

APA, 6th edition

General, U. S. S. (1860). Map of a part of Washington Territory : to accompany the report of the Surveyor General, 1860-61. [Maps]. s.n.], https://collections.library.yale.edu/catalog/15821631.