An animated image showing the U.S. states by date of statehood, that is, the date when each U.S. state joined the Union. Although the first 13 states can be considered to be members of the United States from the date of the Declaration of Independence, they are presented here as being "admitted" on the date each ratified the present United States Constitution. The secession of states to form the Confederacy is not addressed here.Image credit: Astrokey44