Ashton upon Mersey is an area in Trafford, in Greater Manchester, England. It lies on the south bank of the River Mersey, 5 miles south of Manchester city centre and immediately adjoins Sale to the east. It gives its name to the Ashton upon Mersey ward, which covers the main part of the former village. Ashton upon Mersey lies within the historic county …Ashton upon Mersey is an area in Trafford, in Greater Manchester, England. It lies on the south bank of the River Mersey, 5 miles south of Manchester city centre and immediately adjoins Sale to the east. It gives its name to the Ashton upon Mersey ward, which covers the main part of the former village. Ashton upon Mersey lies within the historic county boundaries of Cheshire, and became part of Greater Manchester in 1974.