Costaselva was originally a Squahamian outpost built on a beach along the coast of the Sun Sea. It was not a serious endeavor, so it was abandoned. Later on, bicboi555 of Bicland decided to snatch it for himself to make a city out of the now-abandoned outpost. This was also the beginning of the former nation known as Osliguay, its capital city being Costaselva. Costaselva means “wooded coast” in Portuguese, alleging to its Brazilian population.

Costaselva is a coastal city, with beautiful beaches and rainforest, the actual center of the city being on a former island now peninsula. A new beach was constructed on the south end of town to replace some natural beaches.

Costaselva's culture is a mixture between Latam, Gaumic, and Hong Kong. The Latam influence is most obivious in its name, that being “wooded coast” in Portuguese. The Hong Kong influence is because of the notably high amount of high rises built for such a small city.