Dorset is blessed with a good number of iron age hill forts where the ground has been undisturbed for centuries. Those on the chalk can often be prime sites for orchids and so it is with Badbury, you have to search for them but they are there. The earth walls of the fort are the best places to look. There is lots to see other than orchids, of course, including a couple of species of notable butterflies.
Badbury is always somewhere we mean to go and then do not seem to get round to it. Part of the reason is that it is a very popular spot and can get quite busy in summer. That said, away from the car park and picnic area it can hardly be described as crowded! During the week is fine, best avoided at weekends perhaps and school holidays can see it become something of a children's playground which does not suit everyone.
Built on high ground the fortified area at the top affords lovely views across central Dorset and, on a nice day, are almost worth the visit on their own. If you do visit, take the time to explore the woodland behind the fort, it is especially lovely in spring.