Jamestown Dam & Reservoir

As of September 10, 2026, Jamestown Dam & Reservoir is filled to 25.7% of its total capacity, holding roughly 34 hm³ of water out of a maximum 133 hm³. At this level the reservoir is low.

Over the most recent week on record the fill level has held broadly steady (-0.7 pts), and it sits close to where it was a year earlier.

Across the readings we hold for Jamestown Dam & Reservoir — 1816 data points between September 12, 2021 and September 10, 2026 — the level has ranged from a low of 10.3% (January 25, 2022) to a high of 100.0% (May 21, 2023). On average the reservoir is fullest around May and at its lowest around December.

It is operated by USACE primarily for multiple purposes. It lies within the North Dakota basin at 46.931°N, 98.709°W.