Bierstadt Lake is located 1.3 miles from the trailhead on Bear Lake Road. A very picturesque but crowded lake, Bierstadt Lake provides wonderful views of Hallett and Flattop Mountains.
Park at the trailhead (if you can get your car into this narrow and small lot), and start the steep climb up the trail. The trail switchbacks up the side of a mountain to get to the top of Bierstadt Moraine. The climbing part of this hike is about 1.0 miles long and quite difficult if you aren't used to the altitude. Once you get to the top of the moraine, hike another 0.3 miles to a sign pointing the way around the lake. It is another 0.7 miles around the lake if you wish to take the walk.
The next access to the lake is around the east side where a short trail leads back to the lakeshore. It is a fairly open shore, but there will probably be a lot of people in the way. I tried my luck at fishing for about 15 minutes until I lost several flies in the trees and the people became a little overwhelming.
Overall, it is a nice little hike and if you get to the lake at the right time of the day, the photo of the reflections of the mountains in the lake is great. I wouldn't recommend going during the peak of the season in the Park, but try early season. Less people = a more enjoyable experience.