Check our ArchivesSpace database. About 95% of the Archives' holdings are described there:
Public Interface to ArchivesSpace is: http://pacificu.libraryhost.com/
This searches across the Archives, Museum and Art repositories. Only includes "public" fields, so does not (for example) provide shelving locations.
Staff Interface to ArchivesSpace is: https://pacificu.libraryhost.com/admin - requires username and password. Note: Unlike the public interface, the staff interface only searches one repository at a time, e.g. just the Archives, or just the Museum: make sure you are logged into the correct repository. This is where you need to go to find shelf locations, see information about restrictions on usage, etc.