LANCASTER the county was established in 1183. In the Domesday Book, its lands had been treated as part of Cheshire (whose northern boundary had been the River Ribble) and of Yorkshire. It bordered on Cumberland, , Westmorland, Yorkshire, and Cheshire . It is traditionally divided into the six hundreds of Amounderness, Blackburn, Leyland, Lonsdale, Salford and West Derby. Rather than being divided into hundreds, Westmorland was subdivided into two baronies of Westmorland (or sometimes Appleby) and Kendal. Cumberland county was administratively divided into five wards, rather than the hundreds found in most English counties: Allerdale above Derwent, Allerdale below Derwent Cumberland, Eskdale, Leath. The traditional county town in Cumberland is Carlisle and much of the Lake District is geographically located in Cumberland. The Lancaster ceremonial county currently borders on Cumbria, North Yorkshire, West Yorkshire, and the metropolitan counties of Greater Manchester, and Merseyside; and contains the unitary authorities of Blackpool and Blackburn with Darwen.

CHESHIRE borders the ceremonial counties of Merseyside, Greater Manchester, Derbyshire, Staffordshire (with Stoke-on-Trent), and Shropshire. It also borders the unitary authorities of Flintshire and Wrexham in Wales. Cheshire in the Domesday Book was recorded as a much larger county than it is today. Its northern border was the River Ribble, and it was recorded with eighteenehundreds, six of which were north of the River Mersey. In 1182 the land north of the Mersey became administered as part of the new county of Lancashire instead. Later, the hundreds of Atiscross and Exestan became part of Wales. Over the years the ten hundreds consolidated to just seven — Broxton, Bucklow, Eddisbury, Macclesfield, Nantwich, Northwich, and Wirral.

The etymology of Lancaster is derived from its large and imposing castle (the "caster" part), and the river that runs through it, the Lune (a name deriving from old Celtic sources). Language evolution from the old name of Loncastra, the castle-town on the Lune, gives the modern name of Lancaster. Lancaster gained its first charter in 1193 as a market town and borough, but was not given the status of a city until 1937.

The traditional emblem for the House of Lancaster is a red rose, the Red rose of Lancaster, similar to that of the House of York, which is a white rose. These names derive from the emblems of the Royal Duchies of Lancaster and York in the 15th century. This erupted into a civil war over rival claims to the throne during the Wars of the Roses (1455–1485). The Wars were fought largely by the landed aristocracy and armies of feudal retainers. The House of Lancaster found most of its support in the north and west of the country, while support for the House of York came mainly from the south and east.