The gender of compound nouns takes the gender of the final noun regardless of the other nouns which make up the compound.

e.g.
der Herr + die Abteilung = die Herrenabteilung (gents + department = gents/mens department)
der Schlaf + das Zimmer = das Schlafzimmer (sleep + room = bedroom)
der Tisch + die Lampe = die Tischlampe (table + lamp = table lamp)