As an adult, where did Walt Disney live?

Walt Disney lived several places during his life. Are you asking about his residence at the time of his death?
https://en.wikipedia.org/wiki/Walt_Disney

This question is vague. He was born in Canada, moved from there to Chicago, France, Kansas City, and Los Angeles/Hollywood, where he died December 15, 1966.

https://en.wikipedia.org/wiki/Walt_disney

I think you're looking for the house on Carolwood Drive in Holmby Hills.


Walt Disney built the Carolwood Pacific Railroad on his property in Holmby Hills district of Los Angeles, California where he and his family moved in 1949. The railroad was named for the street on which his home was located — Carolwood Drive.
https://en.wikipedia.org/wiki/Carolwood_Pacific_Railroad

Walt and Lillian Disney moved into the house that was designed to suit them and their children in 1949. By Holmby Hills standards they didn't want a huge house because that would require a staff. They put in a soda fountain so that their girls, Diane and Sharon, could entertain their friends. And then Walt put in a railroad. He put in a eighth scale railroad that ran on 2,615 feet of track and had a 90 foot tunnel that ran under Lilly's flower bed. Disney put in a figure eight, three bridges and a 46 foot trestle. He named the railroad the Carolwood Pacific after the street that his house was on, Carolwood Drive. He built a barn as a control center and designed it after the one that was on his family's farm when he was a youth in Marceline, Missouri. The train had its inaugural run on May 15th, 1950. The success of his backyard train is credited with inspiring Disney to develop theme parks.

Walt Disney died in 1966. His wife Lillian lived in their house in Holmby Hills until her death in 1997. When the property was sold the new owners decided to rebuild and they had the Disney house demolished. The barn was spared and moved to Griffith Park with the help of the Carolwood Pacific Historical Society.
http://disneyexaminer.com/2015/09/10/take-a-closer-look-at-the-hollywood-homes-of-walt-disney/