Cite

Lewis' free soil, slavery, and territorial map of the United States.

MLA

Lewis' Free Soil, Slavery, and Territorial Map of the United States. John Lewis, 1848. https://collections.library.yale.edu/catalog/15603715.

APA, 6th edition

Lewis' free soil, slavery, and territorial map of the United States. (1848). [Maps]. John Lewis, https://collections.library.yale.edu/catalog/15603715.