*US = United States (see also State codes)
*W3 = Wales
Many locations have been part of different countries over the centures. Items are shjelved by the name of the ruling country at the time in question. When works cover a long period, they are shelved under the current name, or rarely under the most common one.
This is a particular challenge for what's now the United Kingdom. While there's a tendency in genealogy to use UK for all areas now included in the country, this is not the case in the field of history. There are many works that pertain only to Scotland, Wales, or Ireland. These works are shelved under those names as a means of subdividing the UK. A very few works address only the period when the name of the country was England or Great Britain, and those are shelved there.
===State Classifications===