Matsalu National Park is a nature reserve and national park situated in Lääne County, Estonia. Matsalu National Park spans an area of 486.1 km2 (187.7 sq mi), comprising Matsalu Bay, the Kasari River delta, and surrounding areas. Matsalu Bay (Estonian: Matsalu laht) is one of the most important wetland bird areas in Europe, due to its prime position on the East Atlantic Flyway. Large numbers of migratory birds use Matsalu as a staging area. Every spring over two million waterfowl pass Matsalu, of which around 1.6 million are Long-tailed Ducks.
Matsalu National Park is a home for a number of endangered species, many of which are listed in the Estonian IUCN Red List, including the White-tailed Eagle of the highest conservation category, a lot of bird species of the second and third protection categories, 22 strongly protected plant species, the Natterjack Toad, and ten species of mammals of the second conservation category.