Caernarfon was a constituency of the National Assembly for Wales from 1999 to 2007.

It was one of nine constituencies in the North Wales electoral region until the abolition of the seat.

The constituency elected one Assembly Member by the first past the post method, while the North Wales region elected four additional members, to produce a degree of proportional representation for the area as a whole.

The Arfon constituency is within the North Wales electoral region.

The Dwyfor Meirionnydd constituency is within the Mid and West Wales region.