Ancient monument

The term ancient monument is a term in British law.
It is an early historical structure or monument. For example. it may be an archaeological site worth preserving and study. The sites (monuments) are of archaeological or heritage interest. 

The term differs from the American term "national monument". The U.S. National Monuments are  few in number and may include natural formations. British ancient monuments are by definition manmade.

Ancient monuments are defined by the Ancient Monuments and Archaeological Areas Act 1979, as
(a) any scheduled monument (there are now more than 20,000) and 
(b) any other monument which in the opinion of the Secretary of State is of public interest for its historic, architectural, traditional, artistic or archaeological interest.

 Related pages 
 English Heritage
 Scheduled monument

References

Other websites
  National Heritage List for England: official list of scheduled ancient monuments in England

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Category:Archaeological sites
Category:United Kingdom law