The constituency was created in 1983, largely replacing the ancient constituency of Merioneth, and was abolished in 2010. For the entire period of its existence, it was represented by Plaid Cymru, and was generally regarded as a safe seat. It had the lowest population of any constituency in England or Wales, and also had the second highest proportion of Welsh-speaking voters.
Following its review of parliamentary representation in Wales, the Boundary Commission for Wales abolished this constituency. It was replaced mostly by Dwyfor Meirionnydd and in part by Aberconwy. These new constituencies were first fought at the 2010 general election.
Members of Parliament
From 1983 to 1992 the constituency was represented by Dafydd Elis Thomas of Plaid Cymru, who represented Dwyfor Meirionnydd in the Welsh Senedd and is its former Presiding Officer. The constituency was represented at its abolition by Elfyn Llwyd, also of Plaid Cymru.