Lesser Slave Lake is a lake located in central Alberta, Canada, northwest of Edmonton. It is the second largest lake entirely within Alberta boundaries (and the largest easily accessible by vehicle), covering 1,160 km2 (450 sq mi) and measuring over 100 km (62 mi) long and 15 km (9.3 mi) at its widest point. Lesser Slave Lake averages 11.4 m (37 ft) in depth and is 20.5 m (67 ft) at its deepest. It drains eastwards into the Athabasca River by way of the Lesser Slave River.