Cite

Colton's map of the states and territories west of the Mississippi River to the Pacific Ocean : showing the overland routes, projected rail road lines, &c.

MLA

G. W., et al. Colton's Map of the States and Territories West of the Mississippi River to the Pacific Ocean : Showing the Overland Routes, Projected Rail Road Lines, &c. G.W. and C.B. Colton, 1870. https://collections.library.yale.edu/catalog/15812957.

APA, 6th edition

G. W., Colton, C. B., & C. (1870). Colton's map of the states and territories west of the Mississippi River to the Pacific Ocean : showing the overland routes, projected rail road lines, &c. [Maps]. G.W. and C.B. Colton, https://collections.library.yale.edu/catalog/15812957.