The long-distance hiking trail 34 (French: Sentier de grande randonnée 34 or GR 34 for short) is a French coastal path that starts from Mont-Saint-Michel (Manche) and ends in Saint-Nazaire (Loire-Atlantique). It runs along almost the entire coast of the Brittany region from Mont Saint-Michel and, beyond the limit between Morbihan and Loire-Atlantique, to the mouth of the Loire. It stretches over 1,700 kilometres (1,100 mi). It largely follows former customs paths. These paths, gradually abandoned during the first half of the 20th century, allowed customs officers to patrol the coast from their guardhouses, located at key observation points on the Brittany coast.