| Unit Pref: | Imperial |
| Settlement Type: | Township |
| Official Name: | Rock Run Township |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Stephenson |
| Leader Title: | Supervisor |
| Leader Name: | Ray Bordner |
| Area Total Sq Mi: | 47.84 |
| Area Land Sq Mi: | 47.82 |
| Area Water Sq Mi: | 0.02 |
| Area Water Percent: | 0.04 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 47 |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Coordinates: | 42.3914°N -89.4639°W |
| Elevation Ft: | 909 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 2153 |
| Blank Name: | FIPS code |
| Blank Info: | 17-177-65143 |
Rock Run Township is located in Stephenson County, Illinois. As of the 2010 census, its population was 2,247 and it contained 969 housing units.[2] The villages of Rock City and Davis are located in the township.
Rock Run is Townships 27 (part) and 28 (part) North, Range 9 East of the Fourth Principal Meridian.
According to the 2010 census, the township has a total area of, of which (or 99.96%) is land and (or 0.04%) is water.[2]
The Norwegian-American Rock Run Settlement was established in 1839. Named after the town of Rock Run, it lay partly in Stephenson, partly in Winnebago County, Illinois.[3]
Carnefix Mill, a three–story stone grist mill was built at Irish Grove south of Davis on Rock Run creek by George Raymer in the 1850s. The mill was still standing in 1970.[4]
Davis Manufacturing Company Mill, built in Davis in 1876, was a -story stone flour mill with four run of stone powered by steam. The mill closed in 1880 and was demolished.[5]
Epplyanna Mill (Section 15) a three–story stone grist mill was built on Rock Run north of Rock City by James Epley in 1854. It ceased operation in 1910. After 1910, it was used as a barn. It was demolished by dynamite in 1955.[6]