A small, attic-like space near the top of the Matterhorn structure does indeed contain a basketball rim, backboard, and floor markings. (This cramped area is smaller in size than a regulation half-court, so the term “basketball court” is used rather loosely here.)
This common piece of Disney lore has it that Disneyland’s Matterhorn house a basketball court because at the time it was built, an Anaheim city ordinance prohibited the building of structures exceeding a certain height
The small area atop the Matterhorn is used as a rest and preparation area for the costumed climbers who sometimes entertain park guests by scaling the mountain. According to the Disney Channel program “Inside Out,” the basketball court came to be when one of these climbers brought in and installed a basketball hoop and backboard for use as an amusement to pass the time when inclement weather or other conditions prevented the climbers from working outside the mountain.