Preston Twp 21 is a privately owned rockfill dam located in Fillmore County, Minnesota, specifically in the city of Preston. This dam serves the primary purpose of flood risk reduction along the Partridge Creek-TR river or stream. With a height of 28.6 feet and a storage capacity of 41.3 acre-feet, Preston Twp 21 plays a vital role in managing water levels and protecting the surrounding area from potential flooding events.

Managed by the Minnesota Department of Natural Resources, Preston Twp 21 is regulated, inspected, and enforced to ensure its structural integrity and functionality. Despite its low hazard potential, this dam has not been rated for its condition assessment. The last inspection was conducted in May 2018, with a scheduled frequency of every 8 years. While there are no emergency action plans currently in place, Preston Twp 21 continues to provide essential flood protection for the community and the environment, highlighting the importance of water resource management and climate resilience in the region.

As an integral part of the St. Paul District within the US Army Corps of Engineers, Preston Twp 21 stands as a significant infrastructure for flood risk reduction in the area. Although there is limited information on the dam's construction history and modifications, its presence and purpose underscore the ongoing efforts to safeguard communities and natural resources from potential water-related disasters. With its strategic location and operational capabilities, Preston Twp 21 remains a key asset for water resource and climate enthusiasts seeking to understand and appreciate the importance of sustainable water management practices in Minnesota.