These floor plans of every level of Hogwarts castle, researched and created by Harper Robinson, take the the tiniest of details from the books into account — read Harper’s notes below and be amazed — as well as the standard structure and architecture of castles over the centuries. While not canon, this map is certainly one of the most well-researched and historically accurate blueprints of Hogwarts that anyone could create.

These maps and notes were updated by Harper after the release of book seven, so although the images still say copyright 2006, they are actually revised as of 18 November 2007.

Notes on the creation of the Hogwarts Castle floor plans by Harper Robertson, reproduced from an archive of Harper’s original website:

This site contains a Hogwarts design which is not only complete, but also accurate. That is, as accurate as is possible, given that, as JK Rowling has said, it is impossible to portray all aspects of Hogwarts correctly. I must admit that, over time, I’ve come to believe her. Nevertheless these designs are an attempt at overcoming the obvious obstacles in order to lay out the world in Rowling’s imagination. My goal is to help readers visualize locations in the books in a new way, giving them even more to imagine and explore. A few years ago I came across a footprint of Hogwarts, drawn by JK Rowling herself. Unfortunately, it looked like this:

Inspired though this masterpiece is, it made my job much more difficult. Architecturally, it presented many problems; I won’t explain them all, but first consider this: Where are the courtyards? There are some squares in that drawing, which is helpful, but they’ve got circles (presumably towers) within them. How useful is a courtyard if it’s got a tower within it? Another problem this footprint presented was the locations of windows. With towers in clusters like that, the castle as a whole would be a gloomy place. My first interpretation of this basic shape reflected two simple goals: the placement of windows, and the creation of courtyards. My second interpretation was much more rectilinear. I was focused on making the castle appear historically accurate, and thus the second draft was born. I studied architecture, focusing on castles, fortresses, palaces, manor houses… anything that would be useful to me as I constructed Hogwarts. (I was very surprised to discover last summer that during my trip to Europe, I could tell the difference between 10th and 15th century cathedral windows at a glance!) Historical accuracy was almost as difficult to achieve as canonical accuracy. There’s a very simple explanation for this: Hogwarts in its entirety is a 13-story Scottish castle from the 11th century. There were no 13-story castles in Scotland in the 11th century! They simply did not exist. (Let me make it clear at this point that I’d already realized that Hogwarts didn’t exist. I had known it ever since the age of eleven, when I hadn’t received my letter. What further proof could there possibly be?) Eventually I decided that, although the Second Draft was a reasonably convincing depiction of a castle, it hadn’t yet become Hogwarts. It was simply too planned out, too perfect. Rowling described Hogwarts as a mishmash of different styles. Being a thousand years old, Hogwarts would have had additions built into it, so it would display a wide variety of architectural fashions. I decided to forego the historically perfectionistic goal I had for the plans, replacing it with the kind of asymmetry that the castle’s quirky personality deserved. With the finalization of my interpretation of Rowling’s footprint, I began looking through the books to find the information I would need. I collected information in four main ways. Firstly, by noting descriptions in the books, I was able to locate some rooms very simply. For instance, Harry enters the Entrance Hall, turns right, and finds the Great Hall. At the back of the Great Hall, behind the High Table, is a door leading into a chamber. (Harry is called into this chamber in order to receive instructions regarding the Triwizard Tournament.) My second method was slightly more complicated: I read through narratives in which Harry and his friends travel from one place to another. If the book tells me that they go up a staircase and find a specific room halfway down the hallway on the right, then I noted that, and was sure to connect all rooms properly. Some narratives involved characters moving from one place to another, but had no clues as to the paths they took. In instances where there was dialogue, I read the words aloud and timed them. How far can Harry walk in, say, 51 seconds? How far in five minutes? I took all of these things into consideration. Finally, I listed the views that characters mention from various windows at different locations within the castle. If the Gryffindor Tower dormitory could see the Whomping Willow, then the floor plans had to reflect that. I collected as much information about the castle as I could, following this procedure as precisely as possible. My checklists filled pages, and my original sketches were revised again and again. Mock-up models helped me with visualization, which was particularly helpful when I needed to figure out which rooms could really see the Quidditch Pitch or Hagrid’s Hut. In October of 2006, I finally completed Hogwarts.

Harper included these notes about the maps on the website and in notes emailed to me: