The historic town centre is situated on a cliff 85 meters high and dominates this part of Kvarner.

With the town of Krk, Omišalj is the oldest living town on the island with a tourist tradition more than 100 years old. 

Around 1000 B.C. the Illyrians lived in Omišalj, then the Romans, and in the 7th century the Croats arrived.

In the 11th century Omišalj was an important centre of Glagolism and literacy, and in the 12th century it was referred to as Castri musculi (from the Latin Ad musculi – the place of shells), while in the 15th century the Frankopan family, lords of Krk, built one of their four castles in Omišalj.

Because of this Omišalj today rightly bears the title of the town-monument.