| Mad River | |
| Pushpin Map: | Maine#New Hampshire#USA |
| Pushpin Map Size: | 250 px |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | States |
| Subdivision Name2: | New Hampshire, Maine |
| Subdivision Type3: | Counties |
| Subdivision Name3: | Coos, NH, Oxford, ME |
| Subdivision Type4: | Townships |
| Subdivision Name4: | Bean's Purchase, NH, South Oxford, ME |
| Length: | 1.4miles |
| Source1: | West Royce Mountain |
| Source1 Location: | Beans Purchase, NH |
| Source1 Coordinates: | 44.3025°N -71.0131°W |
| Source1 Elevation: | 2450feet |
| Mouth: | Cold River |
| Mouth Location: | Evans Notch, ME |
| Mouth Coordinates: | 44.2853°N -71.0044°W |
| Mouth Elevation: | 790feet |
| Tributaries Right: | Middle Branch, South Branch |
The Mad River is a 1.4adj=midNaNadj=mid mountain brook on the Maine–New Hampshire border in the United States, within the eastern White Mountains.[1] It is a tributary of the Cold River, part of the Saco River watershed.
The Mad River rises in New Hampshire in the col between West Royce and East Royce mountains, at an elevation of above sea level. The river quickly drops to the south down the slopes of Royce Mountain, entering Maine and dropping over Mad River Falls, a 70adj=midNaNadj=mid cascade.[2] The river joins the Cold River in the floor of Evans Notch, a narrow pass through the White Mountains.