| Prong Number One | |
| Name Other: | Tributary to Gravelly Branch |
| Map Size: | 180 |
| Pushpin Map: | USA Delaware#USA |
| Pushpin Map Size: | 180 |
| Pushpin Map Caption: | Location of Prong Number One mouth |
| Pushpin Map Alt: | Map of Prong Number One mouth location |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Delaware |
| Subdivision Type3: | County |
| Subdivision Name3: | Sussex |
| Length: | 5.78miles[1] |
| Discharge1 Location: | Gravelly Branch (Collins Pond) |
| Discharge1 Avg: | 16.57cuft/s at mouth with Gravelly Branch[2] |
| Source1: | Parker Branch divide |
| Source1 Location: | about 1.5 miles south-southeast of Oakley, Delaware |
| Source1 Coordinates: | 38.7997°N -75.4678°W[3] |
| Source1 Elevation: | 44feet[4] |
| Mouth: | Gravelly Branch |
| Mouth Location: | about 0.25 miles northwest of Kings Crossroads, Delaware |
| Mouth Coordinates: | 38.7525°N -75.4586°W |
| Mouth Elevation: | 29feet[5] |
| Progression: | Gravelly Branch → Nanticoke River → Chesapeake Bay → Atlantic Ocean |
| River System: | Nanticoke River |
| Tributaries Left: | Maple Marsh and Beaver Dam Branch |
| Tributaries Right: | unnamed tributaries |
| Bridges: | Staytonville Road, DE 16, Smith Haven Road, Beaver Dam Road, Maple Branch Road |
Prong Number One is a 5.78miles long 3rd order tributary to Gravelly Branch in Sussex County, Delaware.
Prong Number One rises about 1.5 miles south-southeast of Oakley, Delaware, and then flows south to join Gravelly Branch about 0.25 miles northwest of Kings Crossroads.[5]
Prong Number One drains of area, receives about 45.4 in/year of precipitation, has a wetness index of 781.58, and is about 11% forested.[2]