Balfour Lake

From Memory Alpha, the free Star Trek reference

Balfour Lake is a body of water located on an Class M planet. It is home to several camping facilities.

Jack and Beverly Crusher brought their son, Wesley, here on his first camping trip sometime between 2349 and 2354. Wesley amused himself by throwing Manta leaves into a bonfire to watch them pop. Beverly was reminded of this trip in 2370 while stranded on planet Kesprytt. (TNG: "Attached")

The location of Balfour Lake was not given in the episode, although it can be presumed that it is on Earth. There are several lakes with that name throughout North America. However, it is also likely that the lake was on another human colony, such as Beverly's homeworld of Caldos II.