Parc Cefn Onn

About Parc Cefn Onn

This grade 2 listed historic park, situated on the northern fringes of Cardiff, is also designated as a Country Park providing access to the footpath network of Caerphilly Mountain. It contains a truly magnificent collection of native and exotic trees set within an intimate valley. Visitors enjoy the stunning scenery and the calm, relaxing atmosphere.

The upper park was originally laid out around 100 years ago by former owner Ernest Prosser, Director of the adjacent Rhymney Valley Railway. Its tumbling streams and winding paths take advantage of the gentle valley containing the Nant Fawr stream.

The streams, ponds, woodlands and other planting make this a rich haven for wildlife. Visitors regularly return to enjoy the park in different seasons.


Visitor information

The park is open from 7am until 30 minutes before sunset.

Parking available on site.


  • Grade 2 listed historic park: Listed on the Cadw Register of Landscapes, Parks and Gardens of Special Historic Interest in Wales.
  • Woodland garden: laid out after 1944 in the southern part of the site
  • The Dingle: the historic northern garden laid out by Ernest Prosser. This area contains a collection of rare and exotic plants (closed to the public from 4 February 2019 for 4 months)
  • Summerhouse and former swimming pool: The pond and summerhouse are early features of the Dingle, constructed to alleviate the symptoms of the tuberculosis suffered by Prosser’s son, Cecil.
  • Coed Transh yr Hebog: a semi natural Oak and Beech woodland lying north of the more formal parkland near the top of Caerphilly mountain
  • Mural artwork: located in the subway at the entrance to the park, telling the story of the park
  • Spring displays: the park is a glorious sight throughout the spring with its floral carpets of spring bulbs and exotic Camellias, Rhododendrons and Azaleas.
  • Autumn colours: the tree and shrub collection provides a rich and colourful seasonal display in autumn.


How to find us

How to find us
Access point GPS (latitude / longitude)
Main entrance 51.5460242 / -3.1883328

What3words: united.lend.tuck

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