Mjørkadalur is a place on the Faroese island Streymoy in the Tórshavnar municipality.
It is the site of a Danish military installation (Island Command Faroes) and NATO early warning radar system. Its official population is 1. Mjørkadalur has no postal code.
The location is at the head of a valley where the clouds can be seen forming to travel over nearby peaks. Considering the dialects in different parts of England, a Yorkshireman might call it a Murky Dale when the valley was foggy.