Library of Congress Subject Headings
Place names are derived from the United States Geological Survey (USGS). U.S. Board on Geographic Names (BGN):
Library of Congress Format Descriptions for Geospatial Data
. The status is noted in each document: some are "full," some "partial," and some "preliminary."
Geographic Names Information System
Geographic Name Information System
Getty Thesaurus of Geographic Names
Utah Government Digital Library: http://digitallibrary.utah.gov/awweb/guest2.jsp