I collect Canada WW2 living in the UK most of my info comes from the web.
I have just got a cover from Operation Eskimo which was held in Saskatchewan at the end of WW2.
On the back of the cover, with the address shown just as "Mrs Hanson (?), Nithi River" in British Columbia, is a date stamp for Nithi River dated the 10th of January 1945.

The only info I can find on the web is about the Nithi River itself. There is no mention of any community with that name and certainly not a post office.
Can anyone help with any info re Nithi River and its post office
AQ