Museum of Nonthaburi buildings
The Museum of Nonthaburi was built in 1910 and originally housed a college based on the English public boarding schools. Financial difficulties forced the college to close in 1925, and the large wooden buildings were then used as the provincial hall until 1992. The Interior Ministry then used the building as a training center until 2008. In 2009 part of the structure was converted to a museum devoted to the art and history of Nonthaburi.
A big portion of the displays are devoted to one of Nonthaburi's most famous products, terra cotta pottery, which is still produced on Koh Kred. Apparently, there's supposed to be more than what I saw, but the additional galleries were closed. The place was, in fact, almost deserted save for one guard outside. For that reason, I wouldn't necessarily recommend a trip up to Nonthaburi just to see the museum, but as part of a trip to Koh Kred or other places, it might be worth a stop.
The museum is right at the Nonthaburi Pier of the Chaophraya Express Boat, which is the end of the regular line of boat service. You'll see the museum as you pull into the pier. Most Nonthaburi-bound buses turn around to head back to Bangkok at the clock tower next to the museum.