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.
Take the left fork to the Oregon Lakes trailhead (1/2 mi); the right fork heads down to the Big Flat; going straight will take you across Oregon Creek up to the state line and Missoula Lake. There is adequate signage at the intersection. The parking at the trailhead is not very big, maybe 5-6 vehicles. Trail #109 takes off at that point and climbs steadily and sometimes steeply for about a 1/2 mile to the lower lake.
At the Lake: The lake is small and shallow. There are fish in the lake but the ones that I have caught are very small brook trout. There are several good camping sites at the lake; one near the outlet and the other near the sloping rock outcrop. This might be an option if the middle lake camping is full or if you just don’t want to pack the rest of the way to the middle lake. 
I attempted to ski into the Oregon’s one winter day and we camped overnight at the trailhead one other winter. It was a grind from Schneider’s cabin up over Charlie Miller saddle.
There was a time when Wally Schneider had a cabin near the bridge and intersection of the Freezeout Pass/Gildersleeve Mine Road. They plowed the road during the winter which made for a great access point to the backcountry. There was only room for a couple vehicles to park. In addition, George Gildersleeve left a cabin open and running water from a spigot during the winter; just had to let George know you wanted to use the cabin. The road to the trailhead used to be the main road coming from Charlie Miller Saddle before it was rerouted to its current location and the section from Miller saddle was abandoned. It held snow well into the summer and usually picked off a truck or two that tried to get over it too soon.
