This is a beautiful trail that I frequent in the summer since my dog loves to cool off in the lake.
You can start this in Sandpoint (just go past Seasons to the end of the road) or Kootenai (where Birch Street ends go down to the water). This trail will hopefully become an official ‘trail’ but isn’t quite yet. Make sure your dog is safe around bikes and not to forget your plastic bags!
There is a website dedicated to this trail here.
View Black Rock Trail in a larger map