English: 4 historical maps of the United States, the bottom half of Plate VII. in the article "United States" in the American version of the Encyclopaedia Britannica, 9th ed.

1830, depicting the dates of states' admissions to the United States, the Arkansas Territory, and various other changes in the 1810s and 1820s with illegible blue text. Total area of the United States in 1830 depicted with a thick blue line, State and Territorial divisions at this date depicted with thin blue lines, & Boundaries of the states and territories in 1880 depicted with a black dot-and-dash line.

1840, depicting the dates of states' admissions to the United States, the Iowa Territory, the Republic of Texas, and various other changes in the 1810s with illegible blue text. Total area of the United States in 1840 depicted with a thick blue line, State and Territorial divisions at this date depicted with thin blue lines, & Boundaries of the states and territories in 1880 depicted with a black dot-and-dash line.

1850, depicting the dates of states' admissions to the United States, the Minnesota, Oregon, Utah, and New Mexico Territories, the Unorganized Territory west of the Indian Country, the Gadsden Purchase, and various other changes in the 1840s with illegible blue text. Total area of the United States in 1850 depicted with a thick blue line, State and Territorial divisions at this date depicted with thin blue lines, & Boundaries of the states and territories in 1880 depicted with a black dot-and-dash line.

1860, depicting the dates of states' admissions to the United States, the Washington, Nebraska, Utah, New Mexico, Kansas, and Minnesota Territories, Indian Country, and various other changes in the 1850s with illegible blue text. slave states [yellow]. Total area of the United States in 1860 depicted with a thick blue line, State and Territorial divisions at this date depicted with thin blue lines, & Boundaries of the states and territories in 1880 depicted with a black dot-and-dash line. La Crosse inexplicibly marked in Minnesota.