Lake Hattie, located in Cass County, Minnesota, is a state-regulated reservoir with a primary purpose classified as "Other." The dam, completed in 1937, is a gravity type structure with a height of 10 feet and a length of 55 feet. The reservoir has a maximum storage capacity of 8,168 acre-feet and a normal storage capacity of 6,716 acre-feet, covering a surface area of 484 acres.

The reservoir is situated on the Pine River, with a drainage area of 85.3 square miles and a maximum discharge capacity of 2,600 cubic feet per second. Despite its low hazard potential and satisfactory condition assessment, the dam undergoes inspections every 8 years to ensure its safety and integrity. Lake Hattie serves as a vital water resource for the region, supporting various ecological functions and providing recreational opportunities for residents and visitors alike.

With its scenic location and important role in water management, Lake Hattie is a significant asset in the St. Paul District of Minnesota. The reservoir's historical significance, coupled with its functional design and regulatory oversight, makes it a noteworthy site for water resource and climate enthusiasts to explore and appreciate.