Bagn is the administrative centre of Sør-Aurdal municipality. It's a small village of about 600 people, but it's the main service centre for the southern part of Valdres. You'll find shops, a petrol station, and the Valdrestunet shopping centre here.
The river Begna runs through the village and has a 16-metre waterfall right in the centre.
Between Bagn and Bjørgo, the E16 passes through the 4.3 kilometre Bagnskleiv tunnel, which opened in 2019. This replaced the old road through Bagnskleiva, a steep and winding climb that was notorious among lorry drivers. The sharp bends and steep gradients caused countless accidents, especially in winter when foreign drivers unfamiliar with Norwegian conditions would get stuck, blocking the entire road. Since the E16 is often the only open mountain crossing between Oslo and Bergen during winter storms, this was a serious problem. The old road is still there on the west side of the valley if you're curious to see what drivers used to face.
From Bagn, a side road leads up the valley to Reinli, where you'll find one of Valdres' stave churches. Reinli Stave Church dates from around 1190 to 1250 and is still in use today. We have a separate point about it if you're planning to visit.