Late Victorian era, the seat is quarter sawn oak...but the back appears to be maybe walnut? or maybe just heavily stained. the seats are caned and it appears to be hand caning....worked through holes rather than a prewoven sheet laid in a groove. Look underneath, that will tell you.
What would they go for? Just one? maybe $30 to $70....depending on where you are....now a set of even 4 would bring more perchair....and if you have 6...very desirable!
And are they all in such great condition?

Everything you said seems to be right- it is woven through the holes, and the back is the same as the seats, just heavily stained. I have 2 of them and they are in good condition. Thank you so much for your knowledgable information!!

Oh my no!! I had a chamber pot chair in the house growing up and have seen more than a few....it's a caned seated diingroom chair.
A chamber chair has a round hole to accommodate the pot and a lid....and many many dining chairs have an apron...mine do! And chamber chairs were mostly used for the sick and elderly....anyone else was expected to make the trip!

If it's a chamber chair, how do you account for the caning?

I have an old chamber pot in my powder room; it holds cleaning supplies. I bought it an an antique shop and it was labelled "Old covered casserole dish"...with a price of $10. I didn't tell the owner what she obviously didn't know

Very astutely perceived lindac92. Every piece is a detective discovery of knowledge and logic in search for the right answer. The design is very Arts and Crafts of the period.