Active groups... get you Closer to the Countryside.

The Town and Country Harriers, TACH, an off-road run from a different pub every Thursday. They also organise off-road races.

Other running clubs, which offer off-road running.

Team Bath AC organises the Famous Cotswold Way Relay.
Bitton Road Runners organise two off-road events - the Hanham Horror and the Sodbury Slog plus a 5K series on the Bristol and Bath Railway Path.
Bristol and West AC organise the Blaise Blaiser in the Blaise Estate and the Bridge Inn 5K series on the cycle track (good pub!)
Great Western Runners, GWR, train on Bristol Downs and in Leigh Woods during the Summer and organise the Tow Path
The Hogweed Trotters include off-road sessions in their training schedule.
Kingswood Triathlon Club - swimming cycling and running (with Bitton Road Runners).
Nailsea Running Club organise the Ironwood Challenge and have-off road training groups in the Summer.
Thornbury Running Club organise the Riverbank
Westbury Harriers train in the Blaise Estate during the Summer.
Weston Athletic Club organise the Beacon Batch Fell Race and the Mendip Muddle and also keep an excellent race calendar.

Hashing - a drinking club with a running problem.

Hash House Harriers local branches of this worldwide non-competitive social jogging club.

Walking groups.

Avon Area Ramblers six local rambling group websites.
The Long Distance Walkers Association provides more strenuous walking challenges.

Green Gym.

Avon Wildlife Trust - their links page is especially useful.
Bristol City Council - mainly co-ordinated by the CREATE Centre.
Conservation Volunteers - do your bit for conservation.
Forest of Avon Team - look after the Community Forest Path and much, much more.
South Gloucestershire Council - especially Countryside and Nature link - watch out for Wild roots and Wildtracks being developed for the future.

Other links.

Easy Runner, Bristol - Bristol's largest and longest-serving specialist running shop, with expert advice and fitting.
Bristol Running Resource - Blogs and resources for runners in Bristol.