Nelson Reservoir, MT

As of 2026-10-12, Nelson Reservoir sits at 2216.17 ft, which is below average for this time of year. Over the past 30 days the level has fallen 0.27 ft.

The most recent reading at Nelson Reservoir is 2216.17 ft (2026-10-12), sourced from the U.S. Bureau of Reclamation. Readings on this page refresh automatically as the agency publishes new data.

The highest level for Nelson Reservoir in our records is 2221.48 ft on 2024-05-06. The lowest is 2208.45 ft on 2022-08-21. Our record covers about 5 years of readings.

Compared with every October in our records, the current level is higher than 37% of them, which we classify as below average for this time of year. Seasonal comparison matters more than the raw number, because most reservoirs draw down predictably through late summer and refill over winter and spring.

Reservoir levels move for four main reasons: rainfall and runoff into the basin, releases through the dam for downstream water supply, power generation or flood control, evaporation during hot months, and seasonal drawdown schedules set by the operating agency. Nelson Reservoir has fallen 0.27 ft over the past 30 days. For the operational reason on any given week, check the U.S. Bureau of Reclamation directly.

Nelson Reservoir is -0.68 ft compared with this date last year (2216.17 ft today). The full-history chart above covers 5 years, with a record high of 2221.48 ft and a record low of 2208.45 ft.