A map of the United States issued by Mitchell as part of his school atlas. This work was first issued in 1839 and was popular enough to be reprinted several times into the 1860s. Although the date on the maps did not change, the geography was amended to reflect new discoveries or altered borders. This example has a fairly narrow date window: Texas is shown as part of the Union but Upper California is shown separate from the United States. The former changed from a separate republic to a U.S. state in 1845, while the outcome of the Mexican American War handed control of Upper California to the United States in 1848. Original colour.