Mae tref Nefyn yn ymledu oddi wrth y clogwyni tuag at mynydd Nefyn a Garn Boduan. Mae Nefyn wedi ei leoli oddeutu chwarter milltir oddi wrth arfordir gogleddol Llyn, (SH305405). Mae hi wedi llwyddo i gadw ei chymeriad er fod y ddwy filltir o draeth tywodlyd wedi bod yn boblogaidd iawn erioed.

Cynhaliodd Edward y cyntaf dwrnament yno yn 1284 i ddathlu ei goncwest dros Gymru. Dengys hyn bwysigrwydd cynnar y dref arfordirol orllewinol yma. Ar Gae Iorwerth y cynhaliwyd y twrnament, a fynychwyd gan farchogion o bob cwr o orllewin Ewrop.

Nid tan yn ddiweddar, pan ddaeth masnach yn bwysicach na amddiffyn, y gwnaeth y Tywysog Du greu 'Bwrdeidref rhydd' yn 1355 ( Roedd y boblogaeth gymraeg wedi ei rhwystro rhag cymryd rhan mewn masnachu, a gweithgareddau eraill a fwynheuwyd gan y dosbarth canol seisnig, a parhaodd Nefyn fel canolbwynt masnach Llyn tan y datblygodd Pwllheli fel prif dref Pen Llyn.)

The town sprawls from the high sweeping cliffs towards the mountains of Garn Boduan and Mynydd Nefyn. Nefyn is situated about a quarter of a mile inland from the Northern coast of Llyn. (SH 305405). Even though the two mile stretch of sandy beach has been popular with families for many years, the old town has managed to keep its character .

A tournament was held here in 1284 by Edward the 1st to celebrate his conquering of Wales. This shows the early importance of this westerly coastal town. The tournament was held on Cae Iorwerth,'Edwards field', and knights from all over western Europe attended.

It wasn't until later when commerce became more important than defence that the black prince in 1355 created a "Free Borough" (The Welsh population was debarred from trade and from other rights enjoyed by the new English Burgesses, and its importance as the main center of commerce in the area remained until Pwllheli flourished.)