Cite

Colton's township map of the state of Iowa / compiled from the United States surveys & other authentic sources ; drawn by Geo. W. Colton ; engraved by J.M. Atwood.

MLA

Colton, J. H., and Co. Colton's Township Map of the State of Iowa / Compiled from the United States Surveys & Other Authentic Sources ; Drawn by Geo. W. Colton ; Engraved by J.M. Atwood. J.H. Colton, 1852. https://collections.library.yale.edu/catalog/15814611.

APA, 6th edition

Colton, J. H., & C. (1852). Colton's township map of the state of Iowa / compiled from the United States surveys & other authentic sources ; drawn by Geo. W. Colton ; engraved by J.M. Atwood. [Maps]. J.H. Colton, https://collections.library.yale.edu/catalog/15814611.