Summary
Total streamflow across the
Monocacy River
was last observed at
440
cfs, and is expected to yield approximately
873
acre-ft of water today; about 9%
of normal.
River levels are low and may signify a drought.
Average streamflow for this time of year is
5,046 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 230 cfs.
However, the streamgauge with the highest stage along the river is the
Monocacy River At Bridgeport
with a gauge stage of 2.62 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 | 2025-12-24 |
| Discharge Volume | 873 ACRE-FT |
| Streamflow |
440.1 cfs
-48.4 cfs (-9.91%) |
| Percent of Normal | 8.72% |
| Maximum |
62,500.0 cfs
2021-09-02 |
| Seasonal Avg | 5,046 cfs |
River Streamflow Levels
| Streamgauge | Streamflow | Gauge Stage | 24hr Change (%) | % Normal | Minimum (cfs) | Maximum (cfs) | Air Temp | Elevation |
|---|---|---|---|---|---|---|---|---|
|
Monocacy River At Bridgeport
USGS 01639000 |
33 cfs | 2.62 ft | -11.73 | |||||
|
Monocacy River At Monocacy Blvd At Frederick
USGS 01642190 |
177 cfs | 1.76 ft | -10.15 | |||||
|
Monocacy River At Jug Bridge Near Frederick
USGS 01643000 |
230 cfs | 1.83 ft | -9.45 |
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.