| Horsepen Arm | |
| Name Other: | Tributary to Marshyhope Creek |
| Map Size: | 180 |
| Pushpin Map: | USA Delaware#USA |
| Pushpin Map Size: | 180 |
| Pushpin Map Caption: | Location of Horsepen Arm mouth |
| Pushpin Map Alt: | Map of Horsepen Arm mouth location |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Delaware |
| Subdivision Type3: | County |
| Subdivision Name3: | Kent |
| Length: | 5.54miles[1] |
| Discharge1 Location: | Marshyhope Creek |
| Discharge1 Avg: | 8.41cuft/s at mouth with Marshyhope Creek[2] |
| Source1: | Marsh Branch divide |
| Source1 Location: | about 0.5 miles east of Anthonys Corner, Delaware |
| Source1 Coordinates: | 38.9811°N -75.6694°W[3] |
| Source1 Elevation: | 60feet |
| Mouth: | Marshyhope Creek |
| Mouth Location: | Hollandsville, Delaware |
| Mouth Coordinates: | 38.9215°N -75.6394°W |
| Mouth Elevation: | 49feet |
| Progression: | Marshyhope Creek → Nanticoke River → Chesapeake Bay → Atlantic Ocean |
| River System: | Nanticoke River |
| Tributaries Left: | unnamed tributaries |
| Tributaries Right: | unnamed tributaries |
| Bridges: | Fox Hunters Road, Whiteleysburg Road |
Horsepen Arm is a 5.54miles long second-order tributary to Marshyhope Creek in Kent County, Delaware. This is the only stream of this name in the United States.[3]
Horsepen Arm rises on the Marsh Branch divide about 0.5 miles east of Anthonys Corner, Delaware, and then flows generally southeast to join Marshyhope Creek at Hollandsville, Delaware.[3]
Horsepen Arm drains of area, receives about 44.8 in/year of precipitation, and is about 6.45% forested.[2]