Territorial gains resulted in the creation of new states:
There were only 13 states when the US's constitution was adopted, but then the territory of the USA got extended and hence the number of states too increased.
The new states were formed after the following ways, by which the territory got extended,
- Louisiana Purchase
- Mexican - American war (Large part of Texas joined USA)
- Oregon Territory (by Oregon treaty signed between USA and Britain)
- Purchase of Alaska and Hawaii's will to join US