Trefarthen

Perthi-Duon Burial Chamber is a Neolithic dolmen located to the west of Brynsiencyn, Anglesey, Wales.

Llanidan is a community in the south of Anglesey, Wales which includes the village of Brynsiencyn (Welsh pronunciation). The parish is along the Menai Strait, about 4 miles north-east of Caernarfon (across the strait). The parish church of St Nidan is near the A4080 highway, a little to the east of Brynsiencyn. The ruins of an earlier parish church survive.

The Anglesey Sea Zoo (Welsh: Sw Môr Môn) is an aquarium and independent research and marine education centre on the south coast of Anglesey island in North Wales. Located just outside the village of Brynsiencyn, Anglesey Sea Zoo claims to be the largest aquarium in Wales and displays over 150 native species.

St Nidan's Church, Llanidan is a 19th-century parish church near the village of Brynsiencyn, in Anglesey, north Wales. Built between 1839 and 1843, it replaced the Old Church of St Nidan, Llanidan, which needed significant repair, providing a place of Anglican worship nearer to the village than the old church. Some items were moved here from the old church, including the 13th-century font, two bells from the 14th and 15th century, and a reliquary thought to hold the remains of St Nidan. The tower at the west end has been described as "top heavy" and looking like "a water tower".The church is still used for worship by the Church in Wales, one of five in a group of parishes in the south of Anglesey. It is a Grade II listed building, a national designation given to "buildings of special interest, which warrant every effort being made to preserve them", in particular because it is regarded as "a distinctive example of pre-archaeological gothic revival work." The 19th-century clergyman and antiquarian Harry Longueville Jones said that it had been built in a "debased barbarous style, showing neither architectural science nor taste".

The Old Church of St Nidan, Llanidan is a medieval church in the community of Llanidan, in Anglesey, North Wales, close to the Menai Strait. The first church on the site was established in the 7th century by St Nidan, the confessor of the monastery at Penmon, Anglesey, but the oldest parts of the present structure, are now closed and partly ruined, date from the 14th century. In about 1500 the church was enlarged by the addition of a second nave on the north side, separated from the earlier nave by an arcade of six arches. During 1839 till 1843 a new church was built nearby to serve the local community, partly due to the cost of repairing the old church. Much of the building was subsequently demolished, leaving only part of the western end and the central arcade. The decision was condemned at the time by Harry Longueville Jones, a clergyman and antiquarian, who lamented the "melancholy fate" of what he called "one of the largest and most important [churches] in the island of Anglesey". Other appreciative comments have been made about the church both before and after its partial demolition. After that a new church was opened, the old church was used as a chapel for funerals for a period of time. It has been restored by the owners of the adjoining house, Plas Llanidan, and is occasionally open to the public. The remaining parts of the church are a Grade II* listed building, a national designation given to "particularly important buildings of more than special interest", in particular because St Nidan's is regarded as "a good example of a simple medieval rural church, enriched by 15th-century additions".In the 12th century, Gerald of Wales said that the church possessed a curious stone carving similar to a thigh that would always return by the next day no matter how far away it was taken. A Norman earl, he recounted, had chained it to a large rock and thrown it into the sea, only for the stone to return to the church by the following morning. A sandstone chest containing bone fragments, possibly are relics of a saint, were found buried beneath the altar. The chest and the church's 13th-century font were relocated to the new church.

Caer Lêb is a Roman and mediaeval site on the Welsh island of Anglesey, west of Brynsiencyn. Its name means "Leaven Castle". It is a low-lying site near the Afon Braint with a double row of pentangular banks (some parts now levelled) and marshy ditches. The original entrance was on the east, other gaps are modern and caused by animals. Based on the excavation of a similar site elsewhere on Anglesey, it may date from the 2nd century BCE.Excavations in 1865 found structures within the enclosure, rectangular buildings on the east and a circular one on the south. Nothing of these can now be seen on the ground. Pottery from the 2nd century to the 4th century was found, and on the north side a layer of periwinkle shells and a mediaeval coin, under a layer of peat.There is a parking area, sufficient for 4-5 cars, by the roadside. A footpath goes southwest on a low ridge, some 2 metres above the Afon Braint, from Caer Lêb over stiles, past the site of the former stone circle of Tre'r Dryw Bach, some 800 metres to Castell Bryn Gwyn and on to the Bryn Gwyn stones and the A4080. 500 metres north-west along the road, by Pont Sarn Las (Green Causeway Bridge), the foundations of three round houses may be visible after a dry summer. A large settlement was recorded in the 19th century, and destroyed in the 1870s by agricultural improvement.

Afon Seiont (Welsh, meaning River Seiont in English) is a river in Gwynedd, Wales which runs into the Menai Strait. Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the village. Its mouth is in the town of Caernarfon, forming a natural harbour as it flows out into the Menai Strait. The Afon Nant Peris provides the main inflow into Llyn Peris which then drains into Llyn Padarn with the addition of the waters of the Afon Arddu which drains the northern slopes of Snowdon. The name of the Roman fort of Segontium, near Caernarfon, is based on the Latinised form of the name 'Seiont'. In the Brythonic language *seg-ontio translates as "strong place".

Menai is the name of an electoral ward in the town of Caernarfon, Gwynedd, Wales. As the name suggests, it borders the Menai Strait. The ward elects councillors to the town council and Gwynedd Council.

Ysgol Syr Hugh Owen is a bilingual comprehensive secondary school for pupils aged 11–18. The school is situated in Caernarfon, Gwynedd, Wales. The school was established in 1894, the first to be built under the Welsh Intermediate Education Act 1889, which was heavily influenced by the educator Sir Hugh Owen, after whom the school was named. As of 2022, there were 937 pupils enrolled at the school. Its current headteacher is Paul Mathews Jones. It serves the town of Caernarfon and the nearby villages, which include; Bontnewydd, Caeathro, Y Felinheli, Llandwrog, Rhosgadfan and Rhostryfan.Welsh is the school's main language of communication and administration. All subjects, except Welsh and English, are taught to all pupils using both languages. According to the latest Estyn report, 90% of pupils speak Welsh with their families and 92% are fluent in the language. The school claims that 98% of pupils were fluent in Welsh in 2016.There is also a sixth form, which enables students to stay at the school for a further two years instead of having to transfer to college.

The Llŷn Coastal Path is a waymarked 146-kilometre (91 mi) long-distance footpath running along the coast of the Llŷn Peninsula from Caernarfon to Porthmadog in Gwynedd, north-west Wales. A large part of the Llŷn Peninsula is designated an Area of Outstanding Natural Beauty.Devised and implemented by Gwynedd County Council and the Countryside Council for Wales, the path opened in 2006, though it has since been changed and improved. This work is continuing as part of the path's integration into the Wales Coast Path, an 870-mile (1,400 km) long-distance walking route around the whole coast of Wales from Chepstow to Queensferry.

Lôn Eifion is part of Lôn Las Cymru, the Welsh National Cycle Route, which is about 400 km (250 mi) long. Lôn Eifion is the section which runs for 20 km (12 mi) from Caernarfon to Bryncir along most of the former Caernarfon to Afon Wen line. This line was that of the Carnarvonshire Railway (later LNWR and London, Midland and Scottish Railway), and joined with the Cambrian Coast Line at Afon Wen. Running alongside for part of the way is the trackbed of the old Nantlle Tramway, along which horse-drawn trams carried slates from the quarries in the Nantlle Valley to the port at Caernarfon from where they were exported. From Caernarfon to Llanwnda Station the Lôn Eifion runs alongside that of the Welsh Highland Railway. At the Llanwnda station the Lon Eifion continues south over Glanrhyd to the A487/A499 Pwheli/Porthmadog roundabout, which prior to the Penygroes bypass, was the site of the old Llanwnda Rail Station on the Carnarvonshire Railway. Crossing the roundabout you join the Llanwnda - Groeslon section of the route Lon Eifion, passing on your right the railway cottages built to serve the railway station. The route continues alongside the A487 before passing underneath the road bridge at Afon Llifon before continuing to the village of Groeslon. Crossing the road at the Tafarn Pennionyn the Lon Eifion continues on the East side of the A487 until crossing over again via a foot bridge. Once over the foot bridge the Lon Eifon cuts through woodland heading due South, passing the rear of Inigo Jones Slate Works and further on to open field land with views to the West of Pontllyfni and Aberdasach and The Rivals until reaching another footbridge at the end of Clynogg Road and continuing down to the roundabout of A487/B4418. Continuing south the Lon Eifion continues to closely follow the A487 until vearing away and more South Westerly at Nebo. It continues on a much quieter and greener route along the old railway line through trees and farm land down to Bryncir.At Bryncir the cycle route deviates from the old railway line and heads westerly and steeply upward through a farm and on to single track road before heading south again into Cricceith.

Caernarvon railway station was a station on the former Bangor and Carnarvon Railway between Caernarfon, Gwynedd and Menai Suspension Bridge near Bangor. The station was closed to all traffic in January 1972. The station has since been demolished and the site redeveloped.