The London recording area defined by the London Natural History Society lies within a 20-mile radius of St Paul's Cathedral. As well as including the former historic county of Middlesex and all the London boroughs forming modern-day Greater London, it overlaps the adjacent counties of Berkshire, Buckinghamshire, Essex, Hertfordshire, Kent and Surrey; some sites therefore fall in more than one recording area/county. In a few instances, the London Area boundary also divides sites, notable examples being Amwell Nature Reserve (Herts) and Queen Mother Reservoir (Berks); for listing purposes and for recording other than tetrad mapping, only the part of any site falling within the 20-mile boundary applies. To check if a location is within the London Recording Area, enter the location name in the Google search box above, and click the search symbol. The result is a location marker on a standard Google map; click your browser's back button to view the location on this map.