| Ballestilla Reef | |
| Map: | Antarctica#South Shetland Islands |
| Map Relief: | yes |
| Location: | Antarctica |
| Coordinates: | -62.7347°N -61.5294°W |
| Archipelago: | South Shetland Islands |
| Area Ha: | 0.38 |
| Length M: | 160 |
| Width M: | 40 |
| Population: | uninhabited |
| Country: | None |
| Treaty System: | Antarctic Treaty |
Ballestilla Reef (Bulgarian: риф Балестиля|rif Ballestilla, in Bulgarian pronounced as /ˈrif bɐlɛˈstilʲɐ/) is the 160 m long in southeast–northwest direction and 40 m wide flat and rocky low-tide elevation off the northwest coast of Snow Island in the South Shetland Islands, Antarctica. Its surface area is 0.38 ha. The vicinity was visited by early 19th century sealers.[1]
The feature is named after the geodetic instrument ballestilla, also known as Jacob's staff or cross-staff; in association with other names in the area deriving from the early development or use of geodetic instruments and methods.
Ballestilla Reef is located at -62.7347°N -61.5294°W,[2] which is 2.25 km northwest of Byewater Point. Bulgarian mapping in 2009.