|Region :||Hodh Ech Chargui|
|Coordinates :||15 ° 35 ′ N , 8 ° 5 ′ W|
|Residents :||16,804 (2005)|
|Time zone :||GMT ( UTC ± 0 )|
Boû Steïlé or Bousteila , Arabic بوصطيلة, is the fourth largest city of the administrative unit Hodh Ech Chargui in the southeast of the West African state of Mauritania .
The place is a few kilometers southwest of the historic ruined city of Koumbi Saleh near the border with Mali .
No information is available for the population before 2000, but it has increased continuously. In 2000 it reached 14,904, in 2005 the city's population was estimated at 16,804. In 2005 it was on the list of the largest cities in Mauritania at position 25 and was the fourth largest city in Hodh Ech Chargui after Adel Bagrou , Boû Gâdoûm and Timbédra and ahead of the capital Néma .