The lake is of mixed glacial and tectonic origins. It is 2,120 m (6,960 ft) long and 1,380 m (4,530 ft) wide, with a maximum depth of 30.6 m (100 ft). The lake is situated in a picturesque environment, surrounded by mountains and forests. The medieval-era Bled Castle stands above the lake on the north shore. The Zaka Valley lies at the west end of the lake.
The lake surrounds Bled Island (Blejski otok), the only natural island in Slovenia. The island has several buildings, the main one being the pilgrimage church dedicated to the Assumption of Mary (Cerkev Marijinega vnebovzetja), built in its current form near the end of the 17th century, and decorated with remains of Mediaeval frescos and a rich Baroque equipment. The church has a 52 m (171 ft) tower and there is a stairway with 99 steps leading up to the building. The church is frequently visited and weddings are held there regularly. Traditionally it is considered good luck for the groom to carry his bride up the 99 steps on the day of their wedding before ringing the bell and making a wish inside the church.