Baseline

The baseline is the line from which the breadth of every maritime zone, the territorial sea, contiguous zone, EEZ, and continental shelf, is measured. The normal baseline is the low-water line along the coast as marked on the coastal state’s large-scale charts (UNCLOS Article 5). Where the coast is deeply indented or fringed with islands, straight baselines may join appropriate points under Article 7, and bays, river mouths, and reefs have their own rules. The choice of baseline shifts the seaward edge of every zone outward.