| Hessel | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | State |
| Subdivision Name2: | North Rhine-Westphalia |
| Subdivision Type3: | Reference no. |
| Subdivision Name3: | DE: 316 |
| Length: | 39.337 km |
| Source1 Location: | Source: Northwest of Halle (Westf.) in the Teutoburg Forest |
| Source1 Elevation: | ca. |
| Mouth Location: | Warendorf-Einen |
| Mouth Elevation: | ca. |
| Basin Size: | 212.528 km2 [1] |
| Discharge1 Location: | at Milte (4,3 km oberhalb der Mündung, Einzugsgebiet: 204,87 km²) gauge[2] |
| Discharge1 Min: | Record low: 0 L/s (in 2005) Average low: 304 L/s |
| Discharge1 Avg: | 2.12 m³/s |
| Discharge1 Max: | Average high: 18.4 m³/s Record high: 33.6 m³/s (in 1986) |
| Tributaries Right: | Casumer Bach, Bruchbach, Aabach, Poggenfahrtgraben, Sandfortbach, Teichwiese, Wöstenbach, Beckstroth, Arenbecke, Speckengraben |
| Tributaries Left: | Alte Hessel, Lüffe Graben, |
| Custom Label: | References |
The Hessel is a 39.3adj=midNaNadj=mid, right tributary of the River Ems in the territory of the North Rhine-Westphalian districts of Gütersloh and Warendorf in northwest Germany.
The river rises northwest of Halle (Westf.) on the Große Egge, crosses the Hermannsweg, flows through the villages of Hesseln and Hörste in Halle borough, then through the borough of Versmold through Oesterweg, continuing through the town of Sassenberg and along the southern edge of Milte in the borough of Warendorf, before emptying into the Ems near Warendorf-Einen.
Tributaries include the Casumer Bach, Bruchbach, Aabach, Poggenfahrtgraben, Sandfortbach, Teichwiese, Wöstenbach, Beckstroth, Arenbecke and the Speckengraben.
The Snake's Head Meadows lie along the Hessel near Sassenberg, one of the few areas in Germany in which this strictly protected wildflower occurs.