Allen is a privately owned irrigation dam located in Sheridan, Wyoming, on Sackett Creek. Built in 1955, this earth dam stands at 35 feet in height and has a storage capacity of 50 acre-feet. The dam serves multiple purposes including fire protection, stock watering, and fish and wildlife habitat enhancement.

Despite its low hazard potential, Allen is in poor condition according to a recent inspection in September 2021. The dam's spillway is uncontrolled, with a width of 50 feet, and it has one outlet valve. The dam is located in a moderate risk area, which underscores the importance of regular monitoring and maintenance to ensure its safety and functionality.

As a vital piece of water resource infrastructure, Allen plays a crucial role in supporting agriculture and wildlife in the area. With its location in a picturesque setting and its historical significance, Allen serves as a reminder of the importance of proper dam management and maintenance in the face of changing climate conditions.