This site is located at the mouth of the Danube River on the Black Sea in Tulcea County, eastern Romania. The core protection area covers 3,124. 4 km2. The Danube River flows into the Black Sea, forming the largest and best-preserved estuarine delta in Europe. In its lakes and swamps, the Danube Delta provides shelter for more than 300 species of birds and 45 species of freshwater fish.