Sailly-sur-la-Lys is a commune in the Pas-de-Calais département in the Nord-Pas-de-Calais region of France.
| 1962 | 1968 | 1975 | 1982 | 1990 | 1999 | 2005 |
|---|---|---|---|---|---|---|
| 1789 | 1924 | 2049 | 2919 | 3889 | 3981 | 4046 |
| Census count starting from 1962 : Population without double counting | ||||||
The prévôté is a fortified building located by the parish cemetery, near the Lys. It includes the remains of the prison and the courts of justice. A chapel dedicated to the Virgin complements the construction. The gateway, which was destroyed in the sixteenth century and rebuilt in 1612, is defended by two towers with mullioned windows. Before the French Revolution, it was the provost himself that represented the abbot (of Saint-Vaast) in all matters civil and judicial.