| Portland Arch Nature Preserve | |
|---|---|
 Portland Arch from the south | |
  Map of Indiana | |
| Location | Fountain County, Indiana |
| Nearest city | Fountain |
| Coordinates | 40°13′07″N 87°20′09″W / 40.21861°N 87.33583°W |
| Area | 435 acres (1.76 km2) |
| Governing body | Indiana Department of Natural Resources |
| Designated | 1973 |
Portland Arch Nature Preserve is a 435-acre (1.76 km2) nature preserve near the Wabash River in Fountain County, Indiana, US, and is a National Natural Landmark. The preserve encompasses the wooded valleys, ravines and rocky cliffs around the lowest section of Bear Creek, which flows northwest toward the Wabash River. Its name comes from the nearby town of Fountain, which was originally named Portland, and from a natural sandstone bridge carved by a small tributary of Bear Creek.
Portland Arch Nature Preserve is managed by the Indiana Department of Natural Resources.