Hiiumaa Second largest island in the NW of Estonia(pop.10,000). Island is the second largest island in Estonia (population approx. 10,000). Hiiumaa Second largest island in the NW of Estonia(pop.10,000). lies west of Estonia's mainland and north of Saaremaa The largest island in Estonia(pop. 31,000). Island. The largest town on the island is Kärdla Town in the NW of Estonia(pop. 4,000). . Hiiumaa Second largest island in the NW of Estonia(pop.10,000). has more than 300 km of coastline, with nearly 200 small islands. The island is famous for hikers as across the land lies 324 km of walking paths. Hiiumaa Second largest island in the NW of Estonia(pop.10,000). has one of the oldest lighthouses in the world - Kõpu Lighthouse which is also open for visitors.