Westerberg, Mountain summit in Coesfeld, Germany.

Westerberg, also called Westerather Berg, is the highest point of the Baumberge at 187.6 m above sea level, located between Billerbeck, Havixbeck and Nottuln. Its summit is crowned by the Longinus Tower, a 30 m observation tower built of Baumberge limestone sandstone, with a café and kiosk on the ground floor.

The Longinus Tower was built between 1897 and 1901 by the Baumberge Society from Baumberger lime sandstone. It stands about 30 metres high on the summit of the Westerberg. The tower was erected as an observation tower and remains the main landmark of the Baumberge hills.

The tower is run by the Baumberge-Verein, the society that built it, and its ground floor holds a café and kiosk; the café calls itself the highest in the Münsterland. From the tower, a converted former airport bus known as the Baumbergschnecke runs sightseeing tours through the wooded hills at 6 km/h.

The tower stands on the summit and can be reached by road from Billerbeck, Havixbeck and Nottuln; the K 19 crosses the northern heights past the Baumberg hamlet and a sandstone quarry. The observation deck requires a head for heights, and the tower is usually open all year. Walks from the tower lead into the Stever valley.

The Baumbergschnecke, a former airport bus converted into a sightseeing bus, leaves from Longinus Tower and crosses the wooded Baumberge at 6 km/h. The tower's café calls itself the highest café in the Münsterland.