The United States of America in 1820

In 1820, the United States had undergone some changes in its administrative divisions. Here are the main administrative divisions during that time:

States: The United States had a total of 23 states in 1820. Since 1800, several new states had been admitted to the Union. The additional states that were admitted by 1820 were Vermont, Kentucky, Tennessee, Ohio, Louisiana, Indiana, Mississippi, Illinois, Alabama, Maine, and Missouri. The original 16 states from 1800 were still part of the Union as well.

Territories: The United States also had several territories under its control in 1820. These territories included the Michigan Territory (encompassing present-day Michigan and parts of Wisconsin, Minnesota, and the Dakotas), the Missouri Territory (encompassing present-day Missouri, Iowa, Nebraska, and parts of Minnesota and the Dakotas), and the Arkansas Territory (including present-day Arkansas and parts of Oklahoma and Missouri).

District of Columbia: The District of Columbia continued to exist as the federal district and seat of the national government, which included the city of Washington, D.C.

It's important to note that the United States was actively expanding its territories during this time, and the administrative divisions continued to change and evolve. The admission of new states and the creation of new territories were ongoing processes as the country expanded westward.