Upper Sunset Lake in Markleeville, California, is a privately owned earth dam completed in 1904 for water supply purposes, specifically for irrigation and water supply. The dam stands at a height of 22 feet with a hydraulic height of 18 feet, creating a reservoir with a storage capacity of 200 acre-feet. Situated along the U Pleasant Vy Creek, the dam has a surface area of 27 acres and serves as a vital water resource in Alpine County.

Maintained by the California Department of Water Resources and regulated by the Safety of Dams division, Upper Sunset Lake has a low hazard potential and is considered to be in satisfactory condition as of the last assessment in 2017. Despite its age, the dam continues to play a crucial role in water management in the region, with regular inspections ensuring its safety and functionality. The surrounding area offers a picturesque setting for water resource and climate enthusiasts to observe the intersection of human infrastructure and natural landscapes.

With its historical significance dating back over a century, Upper Sunset Lake serves as a testament to the importance of water conservation in California. The dam's strategic location and purposeful design contribute to its role in providing water for agricultural and domestic use in the area. As climate change continues to impact water resources, understanding and preserving structures like Upper Sunset Lake becomes increasingly essential for sustainable water management practices in the region.