The modern Gwynedd was one of eight Welsh counties originally created on April 1, 1974 under the Local Government Act 1972. It covered the entirety of the former administrative counties of Anglesey, and Caernarvonshire along with all of Merionethshire apart from Edeyrnion Rural District (which went to Clwyd), and also a few parishes in Denbighshire: Llanrwst, Llansanffraid Glan Conwy, Eglwysbach, Llanddoget, Llanrwst Rural and Tir Ifan.
The county was divided into five districts: Aberconwy, Arfon, Dwyfor, Meirionnydd and Anglesey.
The Local Government (Wales) Act 1994 abolished the 1974 county (and the five districts) on April 1, 1996, and its area was divided: Anglesey became an independent unitary authority, and Aberconwy (which included the former Denbighshire parts) passed to the new Conwy county borough. The remainder of the county was constituted a principal area with the name Caernarfonshire and Merionethshire, reflecting that it covered most of the areas of the two historic counties. As one of its first actions, the Council renamed itself Gwynedd on April 2, 1996. Modern Gwynedd is governed by Gwynedd Council. As a unitary authority the modern entity no longer has any districts, but Arfon, Dwyfor and Meirionnydd remain in use as areas for area committees.
The pre-1996 boundaries were retained as a preserved county for a few purposes such as the Lieutenancy - in 2003 the boundary with Clwyd was adjusted to match the modern local government boundary, so that the preserved county now covers the modern Gwynedd along with Anglesey, and that the borough of Conwy is entirely within Clwyd.
A Gwynedd Constabulary was formed in 1950 from the merger of the Anglesey, Caernarfonshire and Merionethshire forces. A further amalgamation took place in the 1960s when Gwynedd Constabulary was merged with the Flintshire and Denbighshire county forces, retaining the name "Gwynedd". In one proposal for local government reform in Wales, "Gwynedd" had been proposed as a name for a local auhority covering all of north Wales, but the scheme as enacted divided this area between Gwynedd and Clwyd. To prevent confusion, the Gwynedd Constabulary was therefore renamed the North Wales Police.
The Snowdonia National Park was formed in 1951. After the 1974 local authority reorganisation, the park fell entirely within the boundaries of the County of Gwynedd, and was run a as a department of Gwynedd County Council. After the 1996 local government reorganisation, part of the park fell under Conwy Borough County Council, and the park's administration separated from the Gwynedd council. Gwynedd Council does still appoint 9 of the 18 members of the Snowdonia National Park Authority (Conwy council appoints 3, and the National Assembly for Wales appoints the remaining 6).
Locations within Gwynedd:
Llansantffraid Glan Conwy