This is Wales's biggest seat geographically, and is almost entirely rural. It extends across the Welsh Marches, sharing the border with England.
Each July, in Llanelwedd, it hosts the biggest agricultural event in Wales, and one of the largest in Britain, the Royal Welsh Show. This had to be cancelled in 2001 because of foot-and-mouth.
There are, unsurprisingly perhaps, extremes within such a large constituency.
Ystradgynlais in the far south, for example, is a former industrial area. Hit heavily by the collapse of the old heavy industries, it has also recently been hit by the closure of textile and light manufacturing industries.
This is a three-way marginal. From 1945 to 1979, it was a safe Labour seat. It was then held by the Tories until Tom Hooson's sudden death in 1985.
In the ensuing by-election, the seat was won by the Liberal Democrats, by a mere 559 votes - the first time since 1924. Mr Livsey held on in 1987, but only by 56 votes. In 1992, the Conservative snatched the seat back, by 130 votes.
But in 1997, Richard Livsey secured a relatively sound victory, regaining the seat, with a majority of 5,097 votes.