abbreviated Lancs.) is a county in north west England.
The county town is Lancaster although the administrative centre is Preston.
The county palatine boundaries remain the same as those of the pre-1974 county, with the Duke of Lancaster exercising sovereignty rights, later than many other counties.
During Roman times the area was part of the Brigantes tribal area in the military zone of Roman Britain.
When its boundaries were established, it bordered Cumberland, Westmorland, Yorkshire, and Cheshire.
Helens and Wigan were added Blackpool (1904), Southport (1905), and Warrington (1900).
The county boroughs also had many boundary extensions.
The area served by the Lord-Lieutenant (termed now a ceremonial county) covered the entirety of the administrative county and the county boroughs, and was expanded whenever boroughs annexed areas in neighbouring counties such as Wythenshawe in Manchester south of the River Mersey and historically in Cheshire, and southern Warrington.
It did not cover the western part of Todmorden, where the ancient border between Lancashire and Yorkshire passes through the middle of the town.