in figurative sense of "land of make-believe" attested by 1956, from U.S. entertainment park (opened in 1955) created by animator and producer Walter E. Disney (1901-1966).
Entries linking to disneyland
Disney
surname attested from mid-12c. (William de Ysini), from Isigny in the Calvados region of Normandy. Disneyesque, in reference to the cartooning style of U.S. animator and producer Walt Disney (1901-1966), is attested by 1939.