| Opak River Sungai Opak, Kali Opak | |
|---|---|
 Opak River as viewed from Jetis, Bantul | |
  Location of river mouth  Opak River (Indonesia) | |
| Location | |
| Country | Indonesia |
| State | Yogyakarta |
| Region | Bantul Regency, Sleman Regency |
| Physical characteristics | |
| Source | Mount Merapi |
| Mouth | |
• location | Indian Ocean |
| Length | 65 km (40 mi) |
| Basin size | 638.89 km2 (246.68 sq mi) |
Opak River is a river in central south area of Java island, Indonesia.[1]