| Cat Tail Brook | |
| Map: | Cat Tail Brook.JPG |
| Source1 Coordinates: | 40.4406°N -74.7672°W |
| Mouth Coordinates: | 40.4319°N -74.7289°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Progression: | Rock Brook, Beden Brook, Millstone River, Raritan River, Atlantic Ocean |
| Mouth Elevation: | 220feet |
| River System: | Raritan River system |
Cat Tail Brook is a tributary of Rock Brook in central New Jersey in the United States.
Cat Tail Brook originates in Sourland Mountain at 40.4406°N -74.7672°W.[1] It flows southeast until it meets Rock Brook at the edge of Sourland Mountain at 40.4319°N -74.7289°W.[1]