Looks like <location>, from the examples for MARC field 852 at
http://www.loc.gov/marc/bibliographic/ecbdhold.html#mrcb852

>>> [log in to unmask] 2004-02-17 17:14:19 >>>
OK, am working with archival documents, and am stuck on how to deal
with the collection info. I've got:

1) the archive

2) the collection

3) the folder and box info

The collection is easy: just the title on relatedItem "host" with a
typeOfResource collection value of "yes."

3 goes in location (though I suppose could be thought of as belonging
to part?).

Where does 1 go? As a corporate name with a role? As a part of the
location? As a publisher?

Here's where I'm at there:

     <relatedItem type="host">
       <titleInfo>
        <title>American Civil Liberties Union Records</title>
       </titleInfo>
       <typeOfResource collection="yes">mixed
material</typeOfResource>
       <location>
        <physicalLocation>MC#001 Box 1124 Folder 8</physicalLocation>
       </location>
     </relatedItem>

Bruce