South Fork is a private irrigation dam located in Johnson, Wyoming, along the South Fork Crazy Woman River. Completed in 1973, this earth dam stands at 26 feet high and spans 1800 feet in length, providing a storage capacity of 317 acre-feet. Despite its low hazard potential, the dam's condition assessment is rated as poor, with a risk assessment indicating moderate risk level.

The dam features a slide (sluice gate) for outlet gates and an uncontrolled spillway with a width of 250 feet. While the dam is state regulated and subject to inspection, its last assessment in August 2018 revealed a need for maintenance and improvement. The surrounding area covers 25 acres, serving as a crucial resource for irrigation in the region. Water resource and climate enthusiasts may find South Fork to be an intriguing structure with a mix of historical significance and ongoing challenges related to its condition and risk management.