MLA

A Map of the North West Parts of the United States of America ... [by] John Fitch ... Engraved and Printed by John Fitch, 0AD. https://collections.library.yale.edu/catalog/15604305.

APA, 6th edition

A Map of the North West parts of the United States of America ... [by] John Fitch ... (0 C.E.). [Maps]. Engraved and Printed by John Fitch, https://collections.library.yale.edu/catalog/15604305.