Once the two lanes reconnect, they continue eastward along Centre Street, passing the Brockton Hospital before crossing the Beaver Brook into Abington. In Abington, Route 123 crosses Route 18 near the town center before making a quick turn along Washington street and turning eastward again, crossing Old Colony Line tracks once more (adjacent to the Abington MBTA station and Route 58 before heading into Rockland. In Rockland, the route shares a half-mile concurrency with Route 139 before turning northward, then eastward into the town of Hanover. In Hanover, the route crosses through the northern part of town, crossing Route 3 without junction before meeting Route 53 at the village of Assinippi, which provides access between Route 3 and Route 123 at exit 13.