The smallest of the Bangkok district museums I have visited so far is the on of Khlong San district, just across the river from Chinatown. It is located within the public library of Wat Anongkharam (วัดอนงคาราม), named Udom Wittaya library (หอสมุดอุดมวิทยา). I love libraries, just sadly it has only Thai books in this one so there was no point in browsing through the shelves - besides I was coming there in late afternoon and it seemed they were about to close soon anyway.
The museum is in the first floor, just up the stairs and then to the right. When I entered, I asked the clerk at ground floor for the location of the museum with those few Thai words I can say, so she directed me upstairs and gave a warning call to the one upstairs that it has a farang coming for the museum. I guess foreigner are a rare sight in there, like in all of these museums.
The central place of the museum area is taken by a portrait of Somdet Ya, the mother of King Bhumipol. She was educated in this temple, and close by the temple a Somdet Ya garden was established around a reconstructed house of your youth.
Other exhibits include old tools used by the main professions in the district, like those salt drying tools I photographed. There's also a bell from the Khlong Sa-Tha Chin railway - originally the Maeklong railway started in this district, now the endpoint is at Wong Wian Yai. Another nice antique exhibit is a metal shop sign; also shown are a few Khon masks manufactured in the district - Ban Khon Thai (บ้านโขนไทย) is located in Khlong San.
The museum is most worth if you combine the visit with the already mentioned nearby Suan Somdet Ya, and the temple Wat Pichai Yat, which I may write about later as well.