Nelson Dam in Selmar, North Dakota, is a privately owned earth dam constructed in 1975 for recreational purposes. Situated on the Little Muddy River, the dam stands at a height of 24 feet and has a storage capacity of 68 acre-feet. With a surface area of 11.4 acres and a drainage area of 3 square miles, the dam serves as a popular spot for outdoor activities in the Williams County region.

Managed by the North Dakota State Water Commission, Nelson Dam is equipped with an uncontrolled spillway and a single slide gate for water release. Despite its low hazard potential and moderate risk assessment, the dam's condition is currently not rated. The surrounding area offers opportunities for fishing, boating, and other recreational pursuits, making Nelson Dam a valuable asset for water resource and climate enthusiasts looking to explore the natural beauty of North Dakota's landscape.

With its picturesque location and rich ecosystem along the Little Muddy River, Nelson Dam continues to attract visitors seeking a tranquil environment for outdoor recreation. While the dam's risk assessment is moderate, its operational and regulatory standards are overseen by the state, ensuring the safety and sustainability of this recreational water resource. As a key feature in the St. Paul District, Nelson Dam stands as a testament to the balance between human enjoyment and environmental conservation in the North Dakota wilderness.