Katahdin Fall
On the Appalachian Trail going up Katahdin.  No pool at the bottom, though.  
 
Long Falls
Dead River just above Flagstaff Lake.  I didn't like it that much, but, maybe I was just in a bad mood on the day I reviewed it. 
45° 13' 52"N
70° 11' 59"W
The Tubs
On the Appalachian Trail above Carrabassett.  Shallow.
45° 08' 01"N 
70° 11' 01"W
Huston Brook
A community swimming hole above Carrabassett.   
45° 21' 54"N 
69° 56' 20"W
Moxie Fall
A good spot 200 yards up from the fall, but lots of litter.
44° 44' 58"N 
70° 32' 31"W
Tumbledown Pond
Above Weld, ME.  Marginal swimming destination. 
44° 44' 58"N 
70° 32' 31"W
Screw Auger Falls
Grafton Notch State Park.  Shallow basins.  Nearby Mother Walker Falls is also a bust.
44° 34' 16"N
70° 54' 23"W
Step Falls
Wight Brook above the Bear River.  Numerous pools, but none deep enough to qualify as a swimming hole.  Beautiful, though. 
44° 34' 50"N
70° 51' 47"W
Three Pools
On the Swift River above Rumford, ME.  Crowds.
44° 38' 32"N
70° 35' 17"W
Dunn Fall
The Appalachian Trail west of Andover, ME.  Too dark and narrow to merit a visit of itself, but great place to pause on the AT.
44° 39' 41"N
70° 53' 57"W
Bickford Slides
The Caribou-Speckled Mountain Wilderness.  Maybe I missed it, I didn't find anything remotely interesting. 
44° 16' 07"N
70° 59' 28"W
44° 07' 33"N
73° 39' 13"W
Keezar Gorge
Almost makes it into the book, but it's a little too dark and mossy.
44° 11' 53"N
70° 48' 54"W