This was David Lloyd George's seat at Westminster, between 1890 and 1945.
Following the death of the former Liberal Prime Minister, Labour's Goronwy Roberts held the seat until 1974.
Since then former Plaid Cymru leader Dafydd Wigley has not only held the seat, but until 1997 managed to increase his majority at every general election.
He is standing down at this election to concentrate on the National Assembly.
Dafydd Wigley was elected to the Assembly with a huge, 65.8% of the vote.
Caernarfon forms part of the Gwynedd local authority area, whose electors - unsurprisingly - voted in favour of devolution in the 1997 referendum.
Gwynedd council itself is in Plaid Cymru control.
With nearly 80% of the constituents able to speak Welsh, this is the most Welsh-speaking constituency in Wales.
Economically, the area, which includes the Llyn peninsula and parts of Snowdonia, is largely dependent on agriculture and tourism.
Caernarfon itself is dominated by the castle - scene of Prince Charles' Investiture as Prince of Wales, in 1969.