San Francisco's museums have a lovely collections of his etchings but most of them are not on view. However, you can see the ones at the Legion on the web here:
and a review of a 2011 show here: http://www.examiner.com/article/happy-birthday-to-james-mcneill-whistler
James McNeill Whistler: https://en.wikipedia.org/wiki/James_Abbott_McNeill_Whistler
The Case for Beauty: http://www.pbs.org/program/james-mcneill-whistler/
NY Times Obit (1903): http://www.nytimes.com/learning/general/onthisday/bday/0714.html
Lunder Collection: The more than 300 etchings and lithographs that make up the Lunder Collection of James McNeill Whistler represent some of the rarest and most beautiful impressions by this American master.
Freer/Sacker Gallery: https://www.asia.si.edu/exhibitions/online/whistler/intro.htm
His deft marks: http://www.artistdaily.com/blogs/masters/archive/2007/10/15/whistler-s-mark.aspx