England–Wales border

The England–Wales border, sometimes the Anglo-Welsh border, is the border between England and Wales, two countries of the United Kingdom. It runs for 257 kilometres (160 mi), from the Dee estuary, in the north, to the Severn estuary in the south. It has followed broadly the same line since the 8th century, and in part that of Offa's Dyke; the modern boundary was fixed in 1536, when the former marcher lordships which occupied the border area were abolished and new county boundaries were created.

The administrative boundary of Wales was confirmed in the Local Government Act 1972. Whether Monmouthshire was part of Wales, or an English county treated for most purposes as though it were Welsh, was also settled by the 1972 Act, which included it in Wales.

The modern boundary between Wales and England runs from the salt marshes of the Dee estuary adjoining the Wirral Peninsula, across reclaimed land to the River Dee at Saltney just west of Chester. It then loops south to include within England an area south-west of Chester, before rejoining the Dee, and then loops east of the river to include within Wales a large area known as Maelor, formerly an exclave of Flintshire, between Bangor-on-Dee (in Wales) and Whitchurch (in England). Returning to the River Dee as far as Chirk, the boundary then loops to the west, following Offa's Dyke itself for about 2 miles, and including within England the town of Oswestry, before reaching the River Vyrnwy at Llanymynech. It follows the Vyrnwy to its confluence with the River Severn, and then continues southwards, rising over Long Mountain east of Welshpool. East of Montgomery, the boundary again follows the line of Offa's Dyke for about 2 miles, before looping eastwards to include within Wales a large area near Churchstoke. It then runs westwards to the River Teme, and follows the river south-eastwards through Knighton before turning south towards the River Lugg at Presteigne, which is within Wales.

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