Historic Counties Trust until I went looking for a source of digitized county boundaries.
A registered charity in the UK, the Trust website offers:
- a map of the counties, better quality than here,
- county descriptions, with a list of main towns, rivers, geographic highlights, the highest point and area,
- the Historic County Borders Project with freely available digitised borders of the historic counties of the UK. Available in various formats and resolutions, the .kmz format can be directly imported into Google Earth. The full resolution dataset files are large.