The fictional town of Beach City, where Steven Universe takes place, is inspired by various real-world locations, but there's no single place that serves as a direct inspiration for "Amity Beach".
The show's creators have said they draw inspiration from places like:
* Rehoboth Beach, Delaware: The show's creator, Rebecca Sugar, has cited this beach town as a particular influence.
* Ocean City, Maryland: The boardwalk and beach town atmosphere are reminiscent of Ocean City.
* Other coastal towns in the US: The creators likely drew inspiration from various coastal towns across the United States.
However, "Amity Beach" is purely a fictional location within the Steven Universe universe.