| Great Brook | |
| Pushpin Map: | New Hampshire#USA |
| Pushpin Map Size: | 250 px |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | New Hampshire |
| Subdivision Type3: | County |
| Subdivision Name3: | Sullivan |
| Subdivision Type4: | Towns |
| Subdivision Name4: | Acworth, Charlestown, Langdon |
| Length: | 10miles |
| Source1 Location: | Acworth |
| Source1 Coordinates: | 43.2317°N -72.3128°W |
| Source1 Elevation: | 468order=flipNaNorder=flip |
| Mouth: | Cold River |
| Mouth Location: | Langdon |
| Mouth Coordinates: | 43.1372°N -72.4042°W |
| Mouth Elevation: | 93order=flipNaNorder=flip |
| Tributaries Left: | Putnam Brook |
| Tributaries Right: | Jed Brook, Fifield Brook, Little Brook, Brush Meadow Brook, Jewett Brook |
Great Brook is a 10adj=midNaNadj=mid[1] tributary of the Cold River in western New Hampshire in the United States.
Part of the Connecticut River watershed, Great Brook begins in the highlands in the town of Acworth, New Hampshire, and flows southwest through the center of the town of Langdon, joining the Cold River 2miles upstream from the Connecticut River.