Upper Diamond Lake via Fourth of July Trailhead

The trail begins at the 4th of July trailhead, which is located near the Eldora ski area and can be crowded during the summer and weekends. The road is rough in places but passable by any car when dry. From the parking area begin hiking the Arapaho pass trail, which will gently gain elevation through forests with occasional glimpses across the valley. Just after a mile into the hike there will be a trail junction, take the diamond lake trail and begin to descend towards the valley floor.

After 0.5 miles you will cross middle boulder creek, which is beautiful area for photographs, flowers, and small waterfalls. Continue along the trail as you ascend through forest from the valley floor to Diamond lake. Just before diamond lake and approximately 1.8 miles from the trailhead the devil's thumb trail splits to the left. Stay to the right (north/west) and continue to diamond lake. Once at diamond lake (a worthwhile small dayhike in its own right and reportedly good for fishing), continue along the northern shore of the lake on the heavily used trail towards the inlet stream.

Near the inlet stream a small unmarked trail will split to the right and begin ascending the hillside. The trail can be hard to find, if you do not see it, continue to the inlet stream and begin ascending. After several hundred meters the faint trail will become more obvious on the hillside. You will follow this unmaintained trail for the next mile as you pass beautiful meadows of flowers, small tarns, and beautiful mountains. As you reach the top of the ridge separating diamond and upper diamond the trail becomes harder to follow.

From here follow the trail as best you can. However, if you are unable to follow the trail or if you prefer to meander follow the easiest path to the west (uphill). The area consists of wet meadows and some class 2 scrambling over rocks, which range from pebbles to house sized boulders. In approximately 0.5 miles you reach upper diamond lake and your destination.

Notice how alone you feel despite being in the middle of several very popular areas (diamond lake and Arapaho pass) and enjoy every minute of it!! The easiest way to return is to follow the same route back to the trailhead. The more adventurous could continue to climb up to Mt. Jasper but I have not done that route and cannot vouch for its difficulty level