Birkenhead is a town within the Metropolitan Borough o Wirral in Merseyside, England. Historically in Cheshire, it is on the Wirral Peninsula, along the west bank o the River Mersey, opposite the city o Liverpull. The Birkenhead Urban Airie defined as the contiguous built-up airie along the eastern side o the Wirral had a total population of 325,264 in the 2011 Census. In the 2011 census, the Parliamentary constituency o Birkenhead had a population o 88,818. The Birkenhead an Tranmere electoral ward, coverin a much maire wee airie, had a population o 15,879.