The Lake a large area filled with water and sourced by the river that runs through town in Animal Crossing.
The lake is a distinct area of the town marked out on the map and features a small jetty and lily pads growing the center of the lake. Numerous events are hosted here, including the Fishing Tourney, Fireworks Show, Harvest Moon Festival and Countdown. Reflections of fireworks and the moon can be viewed in the water during the events in which they occur. Fish that can be caught in the lake have their habitat labelled as a pond, though this should not be confused with the isolated ponds that can appear throughout town.
In later games, the lake is no longer a distinct area. However towns will generate a section of river that widens significantly into a pool resembling a small lake, but containing river fish. In New Horizons, many of the Mystery Island Tour destinations feature bodies of water that resemble lakes. However they contain the same fish as small ponds.