Getting There: From Superior, take Cedar Creek Road #320 and head toward Missoula Lake and Cascade Pass, 25 miles; stay on the main road as there are several other roads that connect. After coming off Miller Saddle, (about 20 mi) there will be an intersection at the bottom of the drainage. Stay straight crossing Oregon Creek. The right fork at this intersection (road #7763) heads down the hill to the Big Flat; the left fork will take you up to the Oregon Lakes trailhead (1/2 mi).
Starting at Cascade Pass (Missoula Lake saddle) take state line trail #738 North towards the Bonanza Lakes. The state line trail is just across the road from the Cascade Pass sign. The 4-wheeler tract that heads straight up the hill is not it. Head north on this easy and mostly level trail for about 1.5 miles to a low saddle. There, trail (#616) heads down into the head of Cataract Gulch and over to the Bonanza Lakes. Continue straight on trail #738. The trail continues mostly uphill for another 1.3 miles passing several overlooks to both Bonanza Lakes.
The trail then turns downhill for an additional 1.2 miles to a small stream crossing for a total of 4 miles. This small stream coming off the shoulder of Binocular Peak is the only year-round water source that is easily accessible between the Dry Creek Summit and Cascade Pass. The unmarked trail to Frog Lake is straight ahead at the crossing, while the state line trail #738 abruptly starts to climb to the right after the stream crossing. The trail to Frog Lake initially climbs a bit but will soon turn down the hill after you cross a small seep. Be patient and stay on the trail as there are some deadfall and brushy areas that block the trail. It is about 1/3 mile down to the lake. Make note of where you exit the trail at the lake so you can find it on the way out.
Getting There: Take the Dry Creek Road exit off I-90, about 5 miles West of Superior. Cross the railroad tracks on the Southside Highway (#69); after about 3/4 mile, hang a right on Dry Creek Road #342. Continue up Dry Creek Road #342 staying right at the fork to Diamond and Cliff Lakes to the Idaho / Montana state line, a total of about 18 miles.
From there head south on the state line trail #738, the trail takes off sharply to the left just as you reach the state line. There is a year-round water source about 1/3 mile back down the road in the ditch if needed. The trail varies between climbing and some descents, but it mostly climbs to over 7,400 feet near Eagle Cliff Peak (2.65 mi). Along the way there are several great overlooks of Cliff and Diamond Lakes. It is a short walk back up the ridge to the summit of Eagle Cliff Peak and its vistas.
From this point the trail mostly descends, staying on or near the ridgeline with very good views of the main Dry Creek drainage and Hidden Lake. You briefly climb back up to 7,000 feet before descending to the intersection of Dry Creek Trail #151 and USFS Trail #77. This is also a good vantage point to view Heart Lake of Dry Creek. The trail then descends further down to a low saddle directly above Heart Lake and sidehills around Binocular Peak about a mile before dropping sharply down to 6,400 feet and the only reliable and easily accessible water source between Dry Creek and Cascade Pass on the southern shoulder of Binocular Peak for a total of 5.60 miles. I have been to this stream late in the summer and it still has good flow.
From this stream facing back the way you came, the unmarked trail to Frog Lake is straight ahead with trail #738 heading back up the hill to the right. The trail to Frog Lake initially climbs a bit but will soon turn down the hill after you cross a small seep. Be patient and stay on the trail as there are some deadfall and brushy areas that block the trail. It is about 1/3 mile down to the lake.
It will be a bit of a slog back to your starting point at the Dry Creek summit. There are at least 3 trails that leave the state line trail on the Idaho side, stay on the main trail along the ridge. It is interesting that the trailhead and lake elevations are the same, but there are several thousand feet of elevation changes between the 2 points.
At the Lake: Frog Lake is just a pond less than 10 feet deep and it is aptly named as there are a ton of frogs but no fish. There is an old campsite near the outlet. The outlet was dry the one time I was at the lake over a Labor Weekend, so I assume the water would not have a great taste. The inlet area was very swampy, and I did not explore far enough to determine an actual inlet stream. So, I am not sure if any water is physically running into the lake late in the summer. If I was staying overnight at this lake, I would pack water from the small stream at the junction rather than test the water at the lake. This lake would be a viable option if a person wasn't able to make the Bonanza Lakes, Cascade Pass or the Dry Creek summit before dark.
