The municipality of Castro Marim covers an area of around 79 Km2 and it is divided in four civil parishes; Altura, Azinhal, Castro Marim and Odeleite and has approximately 3,000 residents.
Castro Marim has 2 castles that both sit on the top of a hill. The older castle `Castelo`is more intact and the Fortaleza de São Sebastião is more ruined and atmospheric. The area is very popular with bird watchers as there is an unspoilt nature reserve of more than 2,000 hectares which is mainly salt marsh.
For four days each year, Castro Marim holds a medieval festival to celebrate the history of the area.