Measuring at around 3,500 acres (14 km2), it is the largest lake in Indiana built completely above ground, its shores consisting of rock levees on all but two of the lake's six sides both of which were also built up to build the power plant.

Opened to fishing in 1978, Gibson Lake had been a prime source of bass and several types of catfish, bluegill, and carp.

Gibson Lake, due to it never getting colder than 40 °F (4 °C), caused by the hot outflows from the plant's condensers, is known to produce a little dusting of snow every now and then.

[2] The lake temperature very rarely falls below 40 °F (4 °C) at its coldest point, due mainly to the plant's condenser discharges.

This often results in lake-effect snow or heavy frost falling in nearby areas.