Castries is the capital and largest city of Saint Lucia, an island country in the Caribbean. Castries is in a flood plain and is built on reclaimed land. It houses the seat of government and the head offices of many foreign and local businesses. The city is laid out in a grid pattern. Its sheltered harbour receives cargo vessels, ferry boats, and cruise ships. It houses duty-free shopping facilities such as Point Seraphine and La Place Carenage. The city is well served by a bus system and taxi service. St Lucia's main post office is in Castries. Castries is the birthplace of Arthur Lewis, winner of the 1979 Nobel Memorial Prize in Economics.
Castries has a population of over 20,000 people. Castries also forms part of the wider Castries metropolitan area which has a population of over 53,639 people.