Cite

Map of the North West : from explorations by the United States Engineers & Royal Engineers of England and Union & Northern Pacific R.R. surveys.

MLA

Map of the North West : from Explorations by the United States Engineers & Royal Engineers of England and Union & Northern Pacific R.R. Surveys. Lith. by the N.Y. Lithographing, Engraving & Printing Co., Julius Bien, supt., 1870. https://collections.library.yale.edu/catalog/15812958.

APA, 6th edition

Map of the North West : from explorations by the United States Engineers & Royal Engineers of England and Union & Northern Pacific R.R. surveys. (1870). [Maps]. Lith. by the N.Y. Lithographing, Engraving & Printing Co., Julius Bien, supt., https://collections.library.yale.edu/catalog/15812958.