Cousins Beach is a location as well as the main setting in The Summer I Turned Pretty series. It's where Susannah's summer house resides at and where her best friend Laurel and her children Belly and Steven regularly visit her at during their summer vacation. Belly always treasured her time there as it felt like "home" to her.
Many fans have wondered if it is a real place. However, Jenny Han confirmed on her website that it is not a real beach, but it is instead a combination based on several different places. The locations that it is inspired by are Cape Cod, the Hamptons and "just a splash of the Outer Banks".