Distributor regions are primarily associated with a corresponding regional contractor association. They may appear in multiple regions when 1) they have stocking locations that that span span multiple regions, or 2) they are in an area where regional contractor associations overlap.
Insulpedia.com defines a manufacturer as a company that produces products under the company name. The products are generally available through a distribution or fabricator network and described by a technical data sheet available on the company website. A manufacturer may be listed in a category that describes the final form of their product after after fabrication.