The Oval, Caernarfon

Segontium (Old Welsh: Cair Segeint) is a Roman fort on the outskirts of Caernarfon in Gwynedd, North Wales. The fort, which survived until the end of the Roman occupation of Britain, was garrisoned by Roman auxiliaries from present-day Belgium and Germany. It was the most important military base and administrative centre in this part of Britain.

Caernarfon's town walls are a medieval defensive structure around the town of Caernarfon in North Wales. The walls were constructed between 1283 and 1292 after the foundation of Caernarfon by Edward I, alongside the adjacent castle. The walls are 734 m (2,408 ft) long and include eight towers and two medieval gatehouses. The project was completed using large numbers of labourers brought in from England; the cost of building the walls came to around £3,500, a large sum for the period. The walls were significantly damaged during the rebellion of Madog ap Llywelyn in 1294, and had to be repaired at considerable expense. Political changes in the 16th century reduced the need to maintain such defences around the town. Today the walls form part of the UNESCO world heritage site administered by Cadw. Archaeologists Oliver Creighton and Robert Higham describe the defences as "a remarkably intact walled circuit".

Caernarvon (Morfa) was the temporary western terminus of the Carnarvon and Llanberis Railway, located on the southern fringe of Caernarfon, Gwynedd, Wales. The line from Llanberis to Caernarfon was built from the country end, as were the other standard gauge routes to the town, resulting in there being three temporary termini on the edges of Caernarfon. This was eventually resolved by building the "Caernarfon Town Line" through a tunnel under the historic centre to join the various routes. When this was opened Morfa station was closed on 5 July 1870, though it appears that formal paperwork was not concluded until the following January. Freight and passenger trains passed through the station site until 1930, when regular passenger services were withdrawn. Summer excursions to Llanberis passed through until September 1962 and freight lingered on until the line closed in 1964. The tracks were lifted in early 1965.

Caernarfon Barracks is a military installation in Caernarfon, Wales.

Caernarfon Rugby Football Club (Welsh: Clwb Rygbi Caernarfon) is a rugby union team from the town of Caernarfon, Gwynedd, North Wales. They currently play in the Welsh Rugby Union Division One North League. The club was formed in 1973, and the grounds are located at Y Morfa, Lon Parc, Caernarfon. The club colours are maroon and yellow. The club has a First, a Second XV and a Youth team (Under 19). There is an extensive junior section consisting of Under 16, Under 14, Under 13, Under 12, Under 11, Under 10, Under 9 and Under 8 teams.

Caernarfon Station is the northern terminus of the narrow gauge Welsh Highland Railway, located in the town of Caernarfon. It was opened on 11 October 1997 when the line was constructed from Dinas.

The Caernarfon Mithraeum is a Mithraic temple or Mithraeum. It was located 137 meters north-east of the Roman castram of Segontium on the outskirts of modern Caernarfon in Gwynedd, Wales. The remains were discovered by accident on 2 April 1958 and excavated by the National Museum of Wales in August of the following year under the direction of George Boon. The site was found to be already damaged by a sewer trench which cut across the anteroom and had removed part of the southeast corner, but the majority of the temple could be excavated. The excavators noted the site was quite marshy and this suggested that a stream had once flowed close to the temple at the bottom of the shallow valley. The marshy conditions caused the mechanical excavator to frequently fall into the excavation, causing further damage.

The Battle of Twthill took place at Caernarfon in North Wales on 2 November 1401 during the revolt of Owain Glyndŵr. Glyndŵr's success at the Battle of Mynydd Hyddgen the previous June had provided the revolt with fresh impetus, and the battle may be seen as indicative of his determination to foster revolt in the north-west after months of relative inaction in that area. In symbolic terms, the battle is most famous as the first occasion on which Glyndŵr flew his flag bearing a golden dragon on a white field, recalling the symbolism of Uther Pendragon, and thereby more solidly drawing comparisons between his revolt and Welsh political mythology of the time, which drew heavily on the image of the mab darogan or chosen son, who would free Wales from subjugation. Little is known about the particulars of the fighting; the battle ended inconclusively, with 300 Welsh soldiers reported dead, but the isolation of Caernarfon and Glyndŵr's ability to attack English positions in Wales with impunity was amply demonstrated.

Caernarfon (; Welsh: [kaɨrˈnarvɔn] (listen)) is a royal town, community and port in Gwynedd, Wales, with a population of 9,852 (with Caeathro). It lies along the A487 road, on the eastern shore of the Menai Strait, opposite the Isle of Anglesey. The city of Bangor is 8.6 miles (13.8 km) to the north-east, while Snowdonia fringes Caernarfon to the east and south-east. Carnarvon and Caernarvon are Anglicised spellings that were superseded in 1926 and 1974 respectively. Abundant natural resources in and around the Menai Strait enabled human habitation in prehistoric Britain. The Ordovices, a Celtic tribe, lived in the region during the period known as Roman Britain. The Roman fort Segontium was established around AD 80 to subjugate the Ordovices during the Roman conquest of Britain. The Romans occupied the region until the end of Roman rule in Britain in 382, after which Caernarfon became part of the Kingdom of Gwynedd. In the late 11th century, William the Conqueror ordered the construction of a motte-and-bailey castle at Caernarfon as part of the Norman invasion of Wales. He was unsuccessful, and Wales remained independent until around 1283. In the 13th century, Llywelyn ap Gruffudd, ruler of Gwynedd, refused to pay homage to Edward I of England, prompting the English conquest of Gwynedd. This was followed by the construction of Caernarfon Castle, one of the largest and most imposing fortifications built by the English in Wales. In 1284, the English-style county of Caernarfonshire was established by the Statute of Rhuddlan; the same year, Caernarfon was made a borough, a county and market town, and the seat of English government in north Wales.The ascent of the House of Tudor to the throne of England eased hostilities with the English and resulted in Caernarfon Castle falling into a state of disrepair. The town has flourished, leading to its status as a major tourist centre and seat of Gwynedd Council, with a thriving harbour and marina. Caernarfon has expanded beyond its medieval walls and experienced heavy suburbanisation. The community of Caernarfon's population includes the highest percentage of Welsh-speaking citizens anywhere in Wales. The status of Royal Borough was granted by Queen Elizabeth II in 1963 and amended to Royal Town in 1974. The castle and town walls are part of a World Heritage Site described as the Castles and Town Walls of King Edward in Gwynedd.

The Caernarfon Criminal Justice Centre is a Crown Court venue, which deals with criminal cases, in Llanberis Road, Caernarfon, Wales.

Afon Seiont is a Site of Special Scientific Interest (or SSSI) in West Gwynedd, Wales. It is protected by law and has been designated as a Site of Special Scientific Interest since July 1997 in an attempt to protect rare or unique features or species within it. The site has an area of 6.4 hectares and is managed by Natural Resources Wales. This site is designated due to its geological qualities. In Wales, geological sites range from quarries to rocky outcrops and massive sea-cliffs. 30% of SSSIs in Wales are notified for geological and geomorphological features. River Seiont is a small river which flows to the sea at Caenarfon, North Wales. Gwynedd County Council and Caernarfon Harbour Trust own this site, with no public access. The west river bank, and also in a past river cliff located 200m inland, is of particular interest for strata. The exposed rocks include the Arenig and overlying Llanvirn series.

Ysbyty Eryri (English: Snowdonia Hospital) is a health facility in Lôn Parc, Caernarfon, Gwynedd, Wales. It is managed by the Betsi Cadwaladr University Health Board.