Eustace I, count of Boulogne, was a son of Count Baldwin II of Boulogne and Adelina of Holland. He held the county from 1046 until his death in 1049.
He was married to Matilda of Leuven, daughter of Lambert I, Count of Leuven and Gerberga of Lower Lorraine and had three children:
| Preceded by Baldwin II |
Count of Boulogne 1046–1049 |
Succeeded by Eustace II |