| Yanisyarvi | |
| Location: | Republic of Karelia |
| Coords: | 61.9667°N 85°W |
| Pushpin Map: | Russia#Russia Karelia |
| Type: | Impact crater lake |
| Outflow: | Jänisjoki |
| Basin Countries: | Russia |
| Depth: | 11.6m (38.1feet) |
| Max-Depth: | 57m (187feet) |
Lake Yanisyarvi (Russian: Янисъярви; Finnish: Jänisjärvi) is a lake in the Republic of Karelia, Russia, located north of and draining to Lake Ladoga.
The basin of this somewhat circular lake was formed by meteorite impact 700±5 million years ago during the Cryogenian period. The crater is 14km (09miles) in diameter.[1]
Prior to World War II, the lake was thought to be the second known volcanic caldera in Finland (the other was Lake Lappajärvi). Both were eventually recognized as impact craters.