Getting There: Take the Fish Creek Exit on I-90 and proceed up Fish Creek Road #343, then the right fork on road #7750 (Iowa State Research Center) that ends at the Clearwater Crossing in 6.75 miles. The clearwater crossing has a small campground (3 sites), 2 vault toilets and a Forest Service Guard Station.
Take trail #103 that takes off to the right of the Guard Station on an old road. Stay on this trail for about 4.5 miles, this is a very good trail with not a lot of elevation gain, so you can make good time. There will be an unmarked trail that will take off down the hill to the left when you are directly across from the Crater Lake drainage. There is a small campsite next to the creek that is convenient, but could have some mosquitoes and flies early in the year. Cross the North Fork of Fish Creek. When I was much younger, I used to jump across the creek at narrow spot with a couple big rocks but not a recommended move. Also, don’t try the crossing too early in the year as the water can be deep and fast at that point.
This trail does not show on any historical maps that I have used or seen. The trail quickly heads up the hill at a very steep incline and it is unrelenting for the next couple of miles. There are only a couple places where you can get to water on the way to the lake, as Crater Creek stays far away and below the trail for most of the way to the lake. There is a hunting camp about 3/4 of the way to the lake with relative easy and best access to water. If you are out of shape or really loaded down, you will suffer getting to the lake. Even if you start early in the morning, you will be making much of the climb in the heat of the day. This is not an easy hike into the lake. Back when I was young, Gary Chambers, the local Game Warden told me that he would walk his horse down part of the trail due to its steep nature.
At the Lake: Crater Lake is an average sized lake for the Great Burn Area. The lake has just a couple camping sites next to the outlet, but they are well worn due to the horse traffic that has frequented the lake over the years. The Hole-In-The-Wall ranch took a lot of people up to the lake for several years in the 1980-90’s. That almost ruined the fishing. The ranch folded and was sold to Iowa State as a research station, so that curbed the fishing pressure significantly.
The first time I went to the lake was when I was in High School (1970’s), the camping site was relatively small. Fishing can be extraordinary if you hit it at the right time. My son and I hit a hatch one day and we were hooking 12–14-inch cutthroats on every cast; and it didn’t matter if it was spinners or flies. This lasted for about 20 minutes but came to an abrupt stop when the hatch ended. 
There is a marginal trail around the entire lake, but shoreline access can be limited on the far side of the lake. There used to be a very nice pond near the outlet but an avalanche that ran across the lake one winter pushed a bunch of logs into it and wiped it out.
For many years (until the 1980’s) there were no restrictions on motorized vehicles in Fish Creek and along the entire state line. Several times I rode my motorcycle up to the 4.5-mile mark and day hiked into Crater Lake; it sure made the climb up to the lake a lot easier. Once the trails were closed to motorized vehicles, I rode my mountain bike to where the un-named trail takes off. It was a lot of fun coming out on the North Fork Trail.
Extra:The North Fork Trail is a good cross-country ski route. There are no major creek crossings all the way past the Greenwood cabins. One winter day, Chuck Bauer and I skied into Greenwood; it only took us a little over 2 hours as we had great snow conditions that day. When the dude ranches were in full swing, the road was plowed all the way into the Hole-in-the-Wall Ranch (Iowa State). Now I don’t know if that is still the case. There are several private cabins in the area, so they may plow the road. The main ranch was sold to Iowa State as a research center. There is a caretaker at the center, but not sure if that person is there year-round and if the road is plowed. The Nine Mile Ranger District probably would have that information. Since the stock bridge was put in, the West Fork of Fish Creek is also accessible year-round.
