J.K. Rowling spent 3 years as a student at Exeter University in Devon. Whilst a number of places throughout her life influenced the writing of Harry Potter, it is clear that the rolling hills, chocolate box villages, and historical streets of Devon and Exeter were a healthy source of inspiration.
1. Gandy Street - Diagon Alley

The Vaults and Gandy Street

2. Mardon Hall, Exeter University - Gryffindor Common Room

3. The Old Firehouse - The Leaky Cauldron


4. University of Exeter Classics Department - Albus Dumbledore and Professor Binns

Hugh Stubbs - Professor Binns
There is also of course Professor Binns! J.K. Rowling has said in person that Hugh Stubbs, another lecturer at her time in Exeter, is the direct inspiration for the character because he used to send students to sleep with his long lectures.
5. 10 Cathedral Close Door - Room of Requirement

6. The Washington Singer Building, Exeter University - Moaning Myrtle's Bathroom

7. A blustery football game in 1986 at St James' Park - Quidditch
8. The Great Hall, Exeter University - The Great Hall


11. Budleigh Salterton - Budleigh Babberton
Further into Devon is the the village where Horace Slughorn resided at the time of his meeting with Albus Dumbledore and Harry Potter. It almost certainly gave inspiration to "Budleigh Salterton", a village a few miles from Exeter.
Ottery St Mary - Ottery St Catchpole
The home of the Weasleys, the Fawcetts, the Diggorys, and the Lovegoods. Ottery St Catchpole was probably inspired by Ottery St Mary, a village close to Exeter.
11. Dawlish - John Dawlish

12. Chudleigh - Chudley Cannons
Ron Weasley's favourite quidditch team finds its home in the village of Chudleigh, 20 minutes drive from Exeter.
Bonus: Dartmoor - Godric's Hollow

If you do ever decide to visit Devon, make sure you keep your inner eye open for traces of wizards and magic.
P.S. A true Harry Potter fan in Exeter should probably join the university's own Harry Potter Society!
More information can be found by clicking on the following link: www.exeterguild.org/societies/harrypottersociety/