Loughborough Lake is a lake in Eastern Ontario, Canada. The lake is mostly in the municipality of South Frontenac, Frontenac County, except for the southern tip which is in and on the northern border of the separated city of Kingston, and is about 20km north of the town centre of Kingston. Loughborough Lake is in the Great Lakes Basin, is 24km long and 15km2 in area, with many small islands, and has over 160km of shoreline.