Most of Metallica’s The Black Album was recorded at One on One Recording Studios in Los Angeles.
The band began recording there in October 1990, working with producer Bob Rock during sessions that lasted roughly eight months. The studio was in North Hollywood, within the Los Angeles area, and served as the principal recording location for the project.
The musicians also used Little Mountain Sound in Vancouver for about a week. Final overdubs and mixing took place at A&M Studios in Hollywood during June and July 1991, so the album was not made entirely in one building.
This distinction matters because different sources may name North Hollywood, Los Angeles, Vancouver, or Hollywood when describing the sessions. One on One was the main recording studio, while the other locations handled additional work and final production stages.