When each state joined the Union
All 50 states, shaded by when they joined, from the first 13 to Alaska and Hawaii.
Each shade of blue is a span of years; the key shows which. The first 13 states have the strongest blue. Alaska and Hawaii are drawn where they really are, so the map is wide.
Every step in words
Today: Fifty states
Borders as of Borders as of 2000
The original 13 states joined by ratifying the Constitution between 1787 and 1790. The other 37 were admitted by Congress, most of them after years as territories. Alaska and Hawaii, both in 1959, were the last.
New states changed the balance of power in Congress, which is why the admission of states like Missouri, California and Kansas set off fights over slavery. In the late 1800s a wave of western states joined as railroads, farms and mines filled the West.
Where the borders come from
- Atlas of Historical County Boundaries: Historical States and Territories, 1783–2000, The Newberry Library. CC0 (public domain).
- Natural Earth coastlines, lakes and countries (1:50m), Natural Earth. Public domain.
- Dates of statehood and of ratification of the Constitution, U.S. Senate and National Archives. Public domain.
What to keep in mind
- Shapes are each state's borders at the end of 2000, the Atlas's last date; some states' borders were different when they joined (Virginia included West Virginia until 1863, for example).
- Dates for the first 13 states are the days they ratified the Constitution; for the rest, the days they were admitted, from the National Archives and U.S. Senate lists.
- Borders are from the Newberry Library's Atlas of Historical County Boundaries, which records every change to the day, with the law or treaty behind it. To keep the map quick to load, coastlines and borders are smoothed, so small bends and tiny islands are missing.