Wikipedia
Holidayland was a grassy picnic ground located along the western edge of Disneyland, near the area that is now New Orleans Square. It is often referred to as the "lost" land of Disneyland. Opening on June 16, 1957, Holidayland had its own admission gate into Disneyland and could hold up to 7,000 guests for large events. It also had playgrounds, horseshoes, baseball field, volleyball, "the world's largest candy-striped circus tent" (previously used by the short-lived Mickey Mouse Club Circus and Keller's Jungle Killers attractions) and other activities. Food and concessions were available for purchase including beer, which was not sold on the neighboring premises of Disneyland.
Holidayland closed in September 1961 due to its lack of shade, no nighttime lighting or restrooms, and alleged lack of Disney "flavor". According to Disney Legend Milt Albright, Holidayland's manager, "It wasn't any one thing that killed Holidayland. It was just the combined effect of a whole lot of things."
Today, the former location of Holidayland houses support facilities for Disneyland, including show buildings for the Haunted Mansion and Pirates of the Caribbean.