St. Marys River at Rockford OH
USGS Site No: 04180988 • St. Marys River • Mercer County, OH
St. Marys River at Rockford OH on the St. Marys River is currently at 430 cfs (High — 80th percentile for this date) . Gage height: 5.70 ft.
Reading from
Historical Percentile Comparison
Today's discharge compared to the long-term record for October 28 at this station. Percentile rank shows what fraction of historical years had lower flow on this date.
| Percentile | Label | CFS Threshold | Today's Flow |
|---|---|---|---|
| 10th | Very Low threshold | 13 | |
| 25th | Low threshold | 21 | |
| 50th (Median) | Normal (median) | 31 | |
| 75th | High threshold | 144 | |
| 95th | Very High threshold | 1,330 | Today: 430 cfs |
30-Day Hydrograph
Recent discharge plotted against the historical 10th–95th percentile envelope for the same calendar days. Source: USGS daily values + long-term statistics.
30-Day Flow History
| Date | Discharge (CFS) | Gage Ht (ft) |
|---|---|---|
| May 28, 2026 | 309 | — |
| May 27, 2026 | 455 | — |
| May 26, 2026 | 614 | — |
| May 25, 2026 | 616 | — |
| May 24, 2026 | 580 | — |
| May 23, 2026 | 643 | — |
| May 22, 2026 | 599 | — |
| May 21, 2026 | 488 | — |
| May 20, 2026 | 296 | — |
| May 19, 2026 | 123 | — |
| May 18, 2026 | 91 | — |
| May 17, 2026 | 96 | — |
| May 16, 2026 | 111 | — |
| May 15, 2026 | 137 | — |
| Apr 21, 2026 | 130 | — |
| Apr 20, 2026 | 193 | — |
| Apr 19, 2026 | 299 | — |
| Apr 18, 2026 | 490 | — |
| Apr 17, 2026 | 633 | — |
| Apr 16, 2026 | 503 | — |
| Apr 14, 2026 | 103 | — |
| Apr 13, 2026 | 99 | — |
| Apr 12, 2026 | 116 | — |
| Apr 11, 2026 | 150 | — |
| Apr 10, 2026 | 212 | — |
| Apr 9, 2026 | 321 | — |
| Apr 8, 2026 | 564 | — |
| Apr 7, 2026 | 842 | — |
| Apr 6, 2026 | 1,150 | — |
| Apr 5, 2026 | 1,610 | — |
Station Information
- USGS Site No
- 04180988
- State
- OH
- County
- Mercer County
- Coordinates
- 40.6948, -84.6466
- Drainage Area
- 340 mi²
- Datum (ft)
- 787.4
- HUC Code
- 04100004
Flood Stage Thresholds
- Action Stage
- 10.0 ft
- Flood Stage
- 13.0 ft
- Moderate Flood
- 15.0 ft
- Major Flood
- 18.0 ft
Currently 7.30 ft below flood stage.
Recent Extremes
- Max discharge
-
2,080 cfsApr 4, 2026
- Min discharge
-
5 cfsSep 22, 2025
- Days at flood stage
- 0
Computed from the local daily-values archive.
Nearby Gauges
-
St Marys River at Walcot Street at Willshire OHVery High8.3 mi · 372 cfs
-
Blue Creek near Pleasant Mills, INVery High9.9 mi · 10 cfs
-
Beaver Creek Near Celina OHVery High11.7 mi · 71 cfs
-
St. Marys River at Pleasant Mills, INVery High11.8 mi · 342 cfs
-
St. Marys River at Decatur, INHigh18.6 mi · 332 cfs