Allen is a significant earth-type dam located in Kelseyville, California, providing irrigation and water supply for the region. Built in 1955, it stands at a height of 33 feet with a storage capacity of 85 acre-feet. The dam is under state regulation and inspection by the Department of Water Resources, Safety of Dams division, ensuring its safety and compliance with regulations.

Situated on Tr Kelsey Creek, Allen plays a crucial role in managing water resources in Lake County. The dam has a satisfactory condition assessment and is deemed to have a significant hazard potential. Its location within the San Francisco District adds to its strategic importance in water management and conservation efforts. With a surface area of 11 acres and a drainage area of 0.8 square miles, Allen contributes to the overall water supply reliability in the region.

Owned privately, Allen's primary purpose is water supply, serving the community with essential irrigation and drinking water resources. The dam's structural integrity and operational efficiency are maintained through regular inspections, ensuring its continued role in sustaining water resources for the surrounding area. With its historical significance and ongoing importance in water management, Allen stands as a testament to the vital role of dams in ensuring water security and sustainability in California.