Flatrock River should not be confused with Flatrock Creek (disambiguation).
| Flatrock River | |
| Name Other: | Flatrock Creek |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Indiana |
| Subdivision Type5: | Cities |
| Subdivision Name5: | Mooreland, Indiana, Lewisville, Indiana, Rushville, Indiana, Columbus, Indiana |
| Length: | 98miles |
| Discharge1 Location: | Columbus, Indiana [1] |
| Discharge1 Avg: | 649 cu/ft. per sec. |
| Source1: | Driftwood River |
| Source1 Location: | Columbus, Indiana |
| Mouth: | White River |
| Mouth Location: | Mooreland, Indiana, Indiana |
| Mouth Coordinates: | 39.2061°N -85.9336°W |
| Tributaries Left: | White River |
The Flatrock River, also known as Flatrock Creek and other variants of the two names, is a 98adj=midNaNadj=mid[2] tributary of the East Fork of the White River in east-central Indiana in the United States.[3] Via the White, Wabash and Ohio rivers, it is part of the watershed of the Mississippi River, draining an area of .[4]
The Flatrock River rises near Mooreland in northeastern Henry County, and flows generally southwestwardly through Rush, Decatur, Shelby and Bartholomew counties, past the communities of Lewisville, Rushville and St. Paul. It joins the Driftwood River at Columbus to form the East Fork of the White River.[5] The New Hope Bridge and Pugh Ford Bridge span the river in Bartholomew County, Indiana.
In Decatur County it collects the Little Flatrock River, which rises in Rush County and flows southwestwardly,[2] past Milroy.[5]
The United States Board on Geographic Names settled on "Flat Rock River" as the stream's name in 1917, and changed it to "Flatrock River" in 1959. According to the Geographic Names Information System, it has also been known historically as "Big Flat Rock River," "Big Flatrock River," "Flat Rock Creek," and "Flatrock Creek."