The oldest traces of human settlement date back to the Bronze Age[3] and there were grave finds from the Late Roman era.

[8] The first documentary mention of the village "Wilhain" dates from 16 April 1010 of the king and later Emperor Heinrich II of Bamberg, who granted the monastery of Polling the property of a farm in Weilheim in 1010.

When a plague epidemic broke out in Munich in 1521, the Bavarian dukes Wilhelm IV and Ludwig temporarily resided in Weilheim.

[14] Well-known representatives from this time were Georg Petel, Hans Krumpper, and Johann Sebastian Degler.

In 1611, the so-called Trifthof was set up at the Ammer for log drifting,[3][15] where tree trunks were bond together as rafts to carry them along the waterway down to the Amper.

[3][22] 24 people were killed and the train station was destroyed by an air raid in the Second World War on 19 April 1945.