MLA

Company, Northern Pacific Railroad. New and Correct Map of the Lines of the Northern Pacific Railroad and Oregon Railway & Navigation Co. Northern Pacific Railway, 1883. https://collections.library.yale.edu/catalog/15603769.

APA, 6th edition

Company, N. P. R. (1883). New and correct map of the lines of the Northern Pacific Railroad and Oregon Railway & Navigation Co. [Maps]. Northern Pacific Railway, https://collections.library.yale.edu/catalog/15603769.