The hike to Tenas Lakes provides multiple clear blue lakes for great swimming, and amazing views. Its a great short trail as well for overnight backpacking.
Starting from Scott Lake in the Willamette National Forest, take the Benson Lake Trail head that starts at the end of the road. This climbs gradually up to Benson Lake, a large, deep, cold lake. From there follow the trail up until you see a junction and a sign to Tenas Lakes. Follow this trail until you find the lakes.
There are lots of trails that will lead to multiple different lakes all of which have great swimming and if you explore you will find great views. You can also take this trail to the summit of Scott Mountain for a more difficult hike.