The Sea of Galilee is a freshwater lake in northern Israel, part of the Jordan River system. The lake itself is rather small -- only nine miles long and five miles wide, and less than 150 feet deep.
In the Old Testament the lake was known as Chinnereth, which is derived from the Hebrew word for "harp," which describes the shape of the lake (Num. 34:11; Josh. 12:3).
The New Testament contains numerous references to the lake itself, and fishing, the casting of nets, catches and boats. The Romans referred to this lake as the Sea of Tiberias (John 6:1). In the first century cured fish from this lake were sent as far away as Rome.
This small sea is surrounded by a high and almost unbroken wall of hills, on account of which it is exposed to frequent sudden and violent storms. Most of our Lord's public ministry was spent around this body of water -- at least nine very populous cities could be found on the banks surrounding this small sea.