Definition: The word 'Lancashire' is an English county which is part of the West Midlands region in England, although it borders Merseyside to the south-east. Definition: Lancashire is a county in England, part of the West Midlands region. It is located in the north-western section of the country between Manchester and Liverpool, with the River Mersey flowing through its territory from the west to the east. The county has a population of around 1.6 million people. Historically, Lancashire was known as 'Old Lancashire' or simply 'Lancashire'. However, in recent years, it has been redefined as 'The Lancashire County Boroughs Association'.