London is Sherlock’s main filming location and the principal setting of the BBC series Sherlock.
The programme relocates Arthur Conan Doyle’s detective into modern London, using recognisable streets, landmarks and institutions alongside fictionalised versions of Holmes locations. The city is central to the show’s identity because Sherlock’s investigations depend on its transport network, media, police services and dense urban geography.
Production also used locations outside London, including Cardiff and other parts of Wales, for practical filming reasons. This sometimes causes confusion about the show’s filming base, but Cardiff is not the series’s principal story setting.
The exterior used for 221B Baker Street is in North Gower Street, London, while interior scenes were filmed on sets. The distinction between story setting and production location explains why several locations can be associated with the programme.