- Contours Walking Holidays http://www.contours.co.uk/ Contours Walking Holidays specialise in self-guided walking holidays (hiking tours) in England and Wales including many of the National Trails.
- Countrygoer http://www.countrygoer.org Lots of information about travelling the "green" way
- Countryside Access and Activities Network http://www.countrysiderecreation.com/ The Northern Ireland Countryside Access and Activities Network (CAAN) is an umbrella organisation which brings together all groups and bodies which have an interest in, or involvement with, countryside recreation in Northern Ireland
- Countryside Council for Wales http://www.ccw.gov.uk/
- Cromwell's commemorative plaques http://www.cromwellsplaques.com
- Cumbria and the Lake District http://www.golakes.co.uk/
- Cyclists Touring Club http://www.ctc.org.uk/
- Dash4it https://www.dash4it.co.uk/store/index.php?cPath=1 Philips and Ordnance Survey official wholesaler
- Definitive guide to walking in Northern Ireland http://www.walkni.com/
- Disabled Ramblers http://www.disabledramblers.co.uk/ An organisation for disabled people concentrating on countryside matters