卡尔卡松（法语：Carcassonne）是法国朗格多克-鲁西永大区奥德省的一个镇，面积65.08平方公里，人口47,634人（2009年）。

卡尔卡松分为新旧两个城区，分别坐落于奥德河东西两侧。西部的新城区地势较低且占地较广，而东部的老城区则有城墙围绕。卡尔卡松的防御工事最早可回溯到罗马时代。1659年，比利牛斯条约将边境的鲁西永大省割让给法国，卡尔卡松在战略上的重要性才逐渐消失，羊毛纺织业成为主要的经济活动。老城区于1853年由建筑师 Eugène Viollet-le-Duc 开始修复，并于1997年纳入联合国教科文组织的世界文化遗产。

Carcassonne (French: [kaʁ.ka.sɔn]; Occitan:Carcassona [kaɾkaˈsunɔ]; Latin:Carcaso) is a fortified French town in the Aude department, of which it is the prefecture, in the Region of Languedoc-Roussillon.

Occupied since the Neolithic, Carcassonne is located in the Aude plain between two great axes of circulation linking the Atlantic to the Mediterranean sea and the Massif Central to the Pyrénées. Its strategic importance was quickly recognized by the Romans who occupied its hilltop until the demise of the Western Roman Empire and was later taken over in the fifth century by the Visigoths who founded the city. Also thriving as a trading post due to its location, it saw many rulers who successively built up its fortifications, until its military significance was greatly reduced by the Treaty of the Pyrenees in 1659.