 Welchweiler borders in the north on the municipality of Horschbach, in the east on the municipality of Elzweiler, in the south on the municipality of Altenglan, in the southwest on the municipality of Bedesbach and in the northwest on the municipality of Sankt Julian.Welchweiler also meets the municipalities of Ulmet and Bosenbach at single points in the west and southeast respectively.Most of Welchweiler's houses stand alongside the "Kreisstraße" that runs from Glanbrücken to Altenglan on small village streets.