Aimed at driving tourism and growth to every part of the country, it will showcase the very best of the UK to more than 78million global passengers a year.
All 12 regions of the UK are featured, with four attractions from each region selected to be featured in giant 3D installations around the airport.
Passengers from all over the world can snap and share selfies inside frames of the UK’s finest landmarks – including Alnwick Castle.
The frames, which should be in place for several years, also feature facts about each of the destinations.
The other three attractions representing the North East are Newcastle Quayside, Durham and Middlesbrough Institute of Modern Art.
The North East frames can be found in Terminal 5 arrivals, near Café Nero.
David Hawke, head of Alnwick Castle Ventures, said: “Alnwick Castle is one of the UK’s favourite castles and an award-winning, family attraction. Starring as Hogwarts in the Harry Potter films placed it on international visitors’ schedules and we now offer tours in eight languages.
“Promoting Alnwick Castle at Heathrow Airport is a fantastic opportunity to reach a worldwide audience and sprinkle the magic everywhere.”