| Official Name: | Kuh-e Qaleh Sofla |
| Native Name: | كوه قلعه سفلي |
| Settlement Type: | village |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Razavi Khorasan |
| Subdivision Type2: | County |
| Subdivision Name2: | Gonabad |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Kakhk |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Kakhk |
| Population As Of: | 2006 |
| Population Total: | 52 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
Kuh-e Qaleh Sofla (Persian: كوه قلعه سفلي, also Romanized as Kūh-e Qal‘eh Soflá) is a village in Kakhk Rural District, Kakhk District, Gonabad County, Razavi Khorasan Province, Iran. At the 2006 census, its population was 52, in 16 families.