Anywhere depending on artists. Artists such as Maya Lin, Pepon Osorio, and Richard Serra seem to find inspiration from memories. Other artists such as Sally Mann and Bruce Nauman seems to get inspired by their surroundings. In some cases, artists could be inspired by other artists, spirituality, sexuality, identity, etc. A place for Inspiration is unlimited.
I personally find inspiration close to my life. My surroundings, mental state, memory, identity can be used as source of inspiration.