Road 15 crosses right over the Dønfoss waterfall here. It's not a tall waterfall - only about 8 metres - but the river Otta forces itself through a very narrow passage, so there's a lot of power behind it. You'll hear it before you see it.
Right next to the waterfall is Dønfoss Camping. It's a decent campsite, but be aware that some pitches are right along the waterfall. That sounds nice in theory, but the river can be quite loud, so if you're a light sleeper, you might want to pick a spot further back.
There's a Coop grocery shop just 200 metres from the campsite if you need to stock up.