How many original British colonies declared independence to form the United States?

How to get close to this number

The flag is the answer key. It carries thirteen stripes and always has, one for each founding colony, while the stars track the current number of states. A national flag that encodes both the founding count and the present count is unusual, and reading it is faster than recalling any history.

That design choice is the interesting part. The stripe count was frozen at the founding while the star count grows, which means the flag is a historical record and a current census at the same time. An earlier version added a stripe per state and was abandoned once it became clear the pattern would not scale.

The geography is worth knowing alongside the number: all thirteen were on the Atlantic coast, from the far northeast to the southeast, and the entire country west of them was added later by purchase, war and treaty. A founding count of thirteen against a present fifty is a compact summary of two centuries of territorial expansion.