Boomtown

A boom town is a place that has very quick population and economic growth. Boomtowns are usually mining towns where an important mineral resource such as gold, silver, or petroleum has been found. It can happen, for example in a gold rush. Gold rush towns usually shrink and disappear after the gold is dug up. They become ghost towns.
The word can also be used for places that grow for other reasons. This can be the town being near a major city, in a nice climate or near a popular attraction. 
Some examples of California boom towns are Columbia (not the country) and San Francisco.