|leisure = common|
|Using this tag is discouraged, use landuse=* or leisure=*, possibly with designation=common instead.|
|Used on these elements|
|Tools for this tag|
This feature has been labeled as deprecated. The recommended replacement is: landuse=* or leisure=*, possibly with designation=common.
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Common land (a common) is land which has an owner, but over which other people have certain rights. Historically these rights typically included the right to graze livestock, collect firewood, or cut turf. Today they include the rights to use the land for certain leisure activities.
In the UK common land is registered. The rights to use it typically include leisure activities such as walking or running, sightseeing, bird watching, picnicking or climbing. Rights would normally not include camping, lighting a fire, or holding an event without the owner's permission. The UK government published a register of common land in 2012, which is archived here - 
- on Wikipedia