This piece says says a place called Sushi-Ya existed in LA around 1906:
According to Doris Muscatine’s “A Cook’s Tour of San Francisco” (Scribner’s, New York, rev. ed. 1969), Cho Cho in San Francisco, which opened in 1960, had one of the first sushi bars outside of Japan, and its chefs were Tokyo-trained.
The NY Times’ first mention of sushi in the US was in a Craig Claiborne review of a place called Nippon in 1963.