This is an interesting article that has as its highlight a map (that can be enlarged) that showcases the situation of elephants in American zoos. Almost 20 zoos have phased out elephants since 1991, with 4 more zoos due to also phase out elephants. It would be interesting to see a list of zoos that have added elephants since 1991.
In U.S. Zoos, Elephants Get Harder to Find - WSJ
In U.S. Zoos, Elephants Get Harder to Find - WSJ