Robertson, located in Johnson, Wyoming, is a privately owned earth dam built in 1970 for fire protection, stock, and small fish pond purposes. The dam stands at a height of 28 feet with a hydraulic height of 23 feet and a structural height of 28 feet. It has a length of 408 feet and a storage capacity of 74 acre-feet, with a normal storage level of 41 acre-feet. The dam is situated on Terry Draw and is regulated by the Wyoming State Engineer's Office, with state permitting, inspection, and enforcement in place.

Despite being classified as having a low hazard potential, Robertson's condition is assessed as fair, with the last inspection conducted in May 2020. The dam has an uncontrolled spillway type with a width of 25 feet and one uncontrolled outlet gate. In case of emergencies, an emergency action plan (EAP) is not available, and risk assessment indicates a moderate level of risk. With a drainage area of 0 square miles and a surface area of 6 acres, Robertson provides essential water resource management for the surrounding area, serving as a critical infrastructure for fire protection and agricultural purposes.