Finding the hotsprings:
From Nakusp, drive north about 15 mi/24 km up the east side of Upper Arrow Lake on Highway 23, past the St Leon Creek bridge.  Turn right on an old logging road just south of the Highway River bridge and follow it 6.5 mi/10.4 km uphill.  Drop over the edge on a track that ends at a fire ring.  A path plunges down the bank to reach the springs in .25 mi/.4 km.  The springs aren't marked on the forest map.

The approach:
The first clue is a small sign nailed to a tree that reads: "There's no place anything like this place anywhere near this place, so this must be the place!"  Thanks to the volunteer work of Peter Roulston and the Arrow Lake Naturalists of Nakusp, the site is now complete with secluded camping area and outhouse in addition to the soaking boxes.
The next sign welcomes to the visitor, gives a bit of background, and provides a few pointers on enjoying a comfortable soak.  A notice warns about poison ivy -- which flourishes along the path and surrounds the springs.

The hot springs:
Around the bend is the coup de gras -- a plywood soaking box about 7 ft/2 m square with an adjoining box half the size.  A pipe channels water from the 141 degree F/60.5 degree C spring, and a valve regulates the flow.  The recommended technique is to leave it as just a trickle, otherwise it gets far too hot.  A bucket has been provided for adding river water.
The three sided shed offers a dry spot for clothes, and decking span the muddy ground around the springs.  A path leads to the nearby river where those so inclined can take an ice-cold plunge between soaks.  A lush cedar forest wraps the area in total privacy.
Just for the record: A second hotspring on the Halfway River was discovered by the forest Service in 1973 while fighting a forest fire; it's said to lie another 7 mi/11 km upstream in a rocky gorge.  Unfortunately, the terrain  isn't conducive to making a pool, as the springs flows down a rockslide of boulders.  Logging roads follow both sides of the river, and the road on the north bank continues up the broad valley into the high country.