| Conflict: | Battle of Bacsil Ridge |
| Place: | San Fernando, La Union, Philippines |
| Partof: | the Second World War and the Philippines campaign (1944-1945) |
| Result: | Filipino-American victory |
| Units1: | 121st Infantry Regiment, Philippine Commonwealth Army, USAFIP-NL |
| Units2: | Japanese 14th Area Army |
| Commander1: | Russell W. Volckmann George Barnett |
| Commander2: | Tomoyuki Yamashita Toshio Hayashi |
| Strength1: | 121st Infantry 308th Bomb Wing |
| Strength2: | 3,000 armed troops 2,000 unarmed support forces[1] |
| Casualties1: | 877 casualties |
| Casualties2: | 3,322 killed 407 captured |
| Date: | 19 March – 23 March 1945 |
| Coordinates: | 16.6167°N 139°W |
The Battle of Bacsil Ridge began on 19 March 1945. It was one of the continued main battles of the 1944–1945 Philippines Campaign of the Second World War between the Filipino soldiers under the 121st Infantry Regiment, Philippine Commonwealth Army, USAFIP-NL, under the command of American General Russell W. Volckmann,[2] and the Japanese Imperial forces under General Tomoyuki Yamashita, which resulted in the capture of San Fernando, La Union on 23 March 1945, and lead to the subsequent capture Bacnotan, La Union after two months of fighting between the armies and guerilla fighters.[3]