| Magat River | |
| Map Size: | 300 px |
| Pushpin Map: | Luzon mainland#Philippines |
| Pushpin Map Caption: | Magat River mouth |
| Subdivision Type1: | Country |
| Subdivision Name1: | Philippines |
| Subdivision Type2: | Region |
| Subdivision Name2: | Cagayan Valley |
| Subdivision Type3: | Province |
| Length: | 226km (140miles) |
| Discharge1 Location: | Cagayan River |
| Discharge1 Avg: | 540m3/s |
| Source1: | Confluence of the Santa Fe and Marang Rivers |
| Source1 Location: | Aritao, Nueva Vizcaya, Cordillera Central Mountains |
| Mouth Location: | Gamu, Isabela |
| Mouth Coordinates: | 17.0409°N 121.8286°W |
| Mouth Elevation: | 26feet |
| Progression: | Magat–Cagayan |
| Basin Size: | 5200km2 |
The Magat River is a river in the Philippine island of Luzon with a total length of . It originates in the Nueva Vizcaya municipality of Aritao, where the Santa Fe River joins the Marang. It is the largest tributary of the Cagayan River by discharge volume of water, with an estimated drainage area of, roughly twenty percent of the total drainage area of the Cagayan River.
The following are the tributaries of the Magat River by length:
The Magat River Integrated Irrigation System Project, started by the National Irrigation Administration in the 1960s, is one of the Philippine's largest irrigation projects with hydroelectric power generation capacity. Its total cost amounted to US$500 million.[1]
The project is made up of the Magat reservoir, three diversion dams, a large number of irrigation canals and three pumping stations to supply irrigation water for an area of about 97400ha. It is also includes hydroelectric power plants; at Magat reservoir, at Baligatan and Magat mini-hydroelectric power plants in Maris main canal.