When describing a location, it is helpful to be able to provide a meaningful description of where it is. Some people try to do this by using the names of administrative areas. This is not always particularly helpful: I could describe Hendon as being in "Barnet", and this wouldn't be incorrect, just confusing, as Barnet is another town several miles away which gives its name to the borough. I could describe it as being in "London" but this is quite a large area and people would be likely to ask "where in London?". Back to square one!
If, however, I described Hendon as being in "Middlesex", many people would know where that was. Despite the fact that Middlesex is no longer used for any form of administration, it is nevertheless a real geographical county. In fact, I have mentioned Hendon, unqualified, to some people, only to have them say "That's in Middlesex, isn't it?".
I am not saying that we should go back to the old days of having our local government based directly, or even near-directly, on these ancient counties. For a start, there are many places that would not be workable to govern if they were divided on county boundaries. Large cities often cross the boundary and are better treated as a single unit. However, the heritage of places within such cities should not be forgotten. Take, for example, Birmingham. There are parts of three counties within the city. Most of the city is in Warwickshire, but there is also a large part in Worcestershire, and at least two parts of Staffordshire form part of the city as it is currently governed. The city of Sheffield, strongly associated with Yorkshire, includes part of Derbyshire within its boundaries. There is nothing wrong with this. The administrative boundaries were set up for convenience of administration, and not for any wider role. The ancient counties were never altered by administrative changes, and are important cultural entities even today.
I strongly wish to see more people aware of the real counties, proud of their heritage and living with stable geography.
The Association of British Counties
ABC's Gazetteer of British Place Names which provides accurate information on counties and important administrative areas for virtually all settlements within the island of Britain and its immediate offshore islands.