This is an ambitious day hike only because I stated after lunch. The hike to the lake is 5 miles one way with a side trail option to hike up to the summit of Trapper’s Peak, which I did. To access the trail head for Thornton Lake, you must drive a back country road for about 20 minutes up a steep grade dirt road. I had a rental car with normal clearance and it worked fine.
The start of the trail is very easy for the first 1.5 miles. After that point it is a steep climb up for another 3 miles to a saddle. At that point, you can go straight for an ascent of Trapper’s Peak or turn left for the lake. It is another .5 miles but this section is a steep downhill to the lake. Once at the lake there are several places to either camp or enjoy the view of Trapper’s Peak on the right and Mt. Triumph left of center watching over the lake.
Return the way you came for a 10 mile hike. If you wanted to ascend Trappers Peak, I recommend doing that first before descending down to the lake. This way you have an option if it is too late in the day.
