The IJsselmeer, also known as Lake IJssel in English, is a closed-off inland bay in the central Netherlands bordering the provinces of Flevoland, North Holland and Friesland. It covers an area of 1,100 km² with an average depth of 4.5 m. The river IJssel, which the lake was named after, flows into the IJsselmeer.
Location: Netherlands
Primary inflows: IJssel, Overijsselse Vecht
Primary outflows: Wadden Sea (which empties into the North Sea)
Surface area: 1,100 km² (420 sq mi)
Average depth: 4.5 m (15 ft)
Max. depth: 9 m (30 ft)
Surface elevation: −0.4 m (−1.3 ft) (winter) −0.2 m (−0.66 ft) (summer)