[1] De Westereen lies on the edge of the clay ridge of Kollum and Kollumersweach.

The place name refers to the fact it lies on the western end of it, on the edge of lower-lying peat area.

[5] For Zwaagwesteinde it was decided the follow the name in the local form of the West Frisian language, De Westereen.

In West Frisian the preferred spelling was until then De Westerein, which was on the town sign together with the Dutch name Zwaagwesteinde before the change.

[6] Today, the official name De Westereen is used in both standard West Frisian and Dutch.