MLA

General, United States. Surveyor. Map of a Part of the Territory of Washington : to Accompany Report of Surveyor General, 1855. Surveyor General's Office, 1855. https://collections.library.yale.edu/catalog/15821628.

APA, 6th edition

General, U. S. S. (1855). Map of a part of the territory of Washington : to accompany report of Surveyor General, 1855. [Maps]. Surveyor General's Office, https://collections.library.yale.edu/catalog/15821628.