Red Flag Warning
2025-12-17T18:00:00-07:00

* AFFECTED AREA...Fire Weather Zones 241, 242, 243, 245 and 246. * TIMING...Until 6 PM MST this evening. * WINDS...West 15 to 30 mph with gusts up to 60 mph. * RELATIVE HUMIDITY...As low as 16 percent. * IMPACTS...Conditions will be favorable for rapid fire spread. Avoid outdoor burning and any activity that may produce a spark and start a wildfire.


Monocacy River River Levels

Last Updated: December 17, 2025

The Monocacy River is a 58-mile-long tributary of the Potomac River that flows through Maryland and Pennsylvania.


Summary

Total streamflow across the Monocacy River was last observed at 292 cfs, and is expected to yield approximately 580 acre-ft of water today; about 17% of normal. River levels are low and may signify a drought. Average streamflow for this time of year is 1,698 cfs, with recent peaks last observed on 2021-09-02 when daily discharge volume was observed at 62,500 cfs.

Maximum discharge along the river is currently at the Monocacy River At Jug Bridge Near Frederick reporting a streamflow rate of 168 cfs. However, the streamgauge with the highest stage along the river is the Monocacy River At Bridgeport with a gauge stage of 2.21 ft. This river is monitored from 3 different streamgauging stations along the Monocacy River, the highest being situated at an altitude of 332 ft, the Monocacy River At Bridgeport.

River Details

Last Updated 2025-12-15
Discharge Volume 580 ACRE-FT
Streamflow 292.3 cfs
-96.5 cfs (-24.82%)
Percent of Normal 17.21%
Maximum 62,500.0 cfs
2021-09-02
Seasonal Avg 1,698 cfs
       
River Streamflow Levels
Streamgauge Streamflow Gauge Stage 24hr Change (%) % Normal Minimum (cfs) Maximum (cfs) Air Temp Elevation
Monocacy River At Bridgeport
USGS 01639000
11 cfs 2.21 ft -36.52
Monocacy River At Monocacy Blvd At Frederick
USGS 01642190
113 cfs 1.58 ft -32.74
Monocacy River At Jug Bridge Near Frederick
USGS 01643000
168 cfs 1.55 ft -17.24
Seasonal Discharge Comparison
Maximum Streamflow Discharge
Streamflow Elevation Profile

The Monocacy River is a free-flowing left tributary to the Potomac River, which empties into the Atlantic Ocean via the Chesapeake Bay. The river is 58.5 miles (94.1 km) long, with a drainage area of about 744 square miles (1,930 km2). It is the largest Maryland tributary to the Potomac.
The name "Monocacy" comes from the Shawnee name for the river Monnockkesey, which translates to "river with many bends." (However, another local tradition asserts that "Monocacy" means "well-fenced garden" in an Indian language.) The first town ever settled in Western Maryland, Monocacy, also gets its name from this river.
The Monocacy National Battlefield lies alongside part of the river, marking an 1864 engagement during the American Civil War, the Battle of Monocacy Junction. The Chesapeake and Ohio Canal crosses over the river at the Monocacy Aqueduct, the largest of the 11 aqueducts on the canal.