There’s nothing wrong with the Thermenmuseum, the Museum of the Roman Baths, in Limburg. It is a large, modern hall in which you can see the remains of the bathhouse of ancient Coriovallum, the largest Roman ruin in the Netherlands. It is pretty well preserved, and is so well understood that it could be rebuilt in Archeon.
There are several exposition rooms, where many finds are shown, together with several reconstructions of scenes of ancient daily life, including a potter’s workshop. There are also models: of the bathhouse, of course, but also of a farm. Explanatory signs and displays are far above average, you can buy some books about the finds, there is a nice temporary exposition – it is, plain and simple, a good museum.
There’s nothing wrong with the Thermenmuseum in Heerlen. And yet, it is always deserted. I have been there five or six times now, and I have never seen a soul. I suspect that it is indeed poorly visited, because a couple of years ago, there was some talk about closing it. That’s not because the town of Heerlen is inhabited by barbarians, but because the Netherlands are a small country; two archaeological museums is sufficient – Nijmegen and Leiden. Worse, within 150 kilometers from Heerlen are the museums of Bonn, Cologne, Xanten, Nijmegen, and Tongeren. There may be nothing wrong with the Thermenmuseum, but it is located at the wrong place. Nevertheless, I am happy that it hasn’t been closed down, like the museum in nearby Maastricht. The Thermenmuseum is truly one of the nicest places in the south of the Netherlands.
The Thermenmuseum is open from 10-17, except on Sunday, when it opens at 12, and on Monday, when it is closed. Your map is here.