It flows through Central, Mariaberg, Sint-Willemstad and Drenthe Parish, where it flows into the Mediterranean Sea. The Martiges is formed by three small creeks, the Hoge, West Lage and East Lage, which are born in the Central Ranges. These converge to form the Martiges. For Much of its course it flows through the mountains but in Mariaberg and Sint-Willemstad the river opens up into a lowland where it meanders along until reaching the sea.
For much of Brunant's history, the river was a vital means for transporting goods and other materials inland, something which the French exploited during the Franco-Brunanter War. With the laying out of roads and railways, the river has lost much its transportation importance.