Thank you for including the wikipedia link, Erilaz.It seems Carnegie Libaries were built in four of the cities of the two California counties I collect. Looks like I'll be hunting for these.
I've seen a few copies, un-used.
Ukiah and Willits, in Mendocino County are both still standing, but used for another purpose.
Eureka and Ferndale in Humboldt county are both still standing, Eureka was restored by the Humboldt Arts Council and is now the Morris Craves Museum of Art.
Ferndale is the only Carnegie Grant Library in northwestern California still functioning as a library!