Locations of Azkaban and Durmstrang Revealed!
by Christina Olanick
JKR said Azkaban is on an island in a sea north of the North Sea. Unless this sea is unplottable (and it seems unlikely to me that they could make a whole sea unplottable), there is only one sea that is north of the North Sea: Barents Sea. Barents Sea is rather far east in terms of European geography, and is adjacent to the mountainous northern coast of Scandinavia (Norway and Russia both have coasts on Barents Sea).
Now this is what we know about Durmstrang: it has a Germanic name, a Slavic headmaster, is so far north that there is very little daylight in the winter months, and it is in a mountainous region with lots of lakes. This information all seems to point to one country: Norway.
Since Krum complains of very short daylight hours in the winter at Durmstrang, it has to be at latitude significantly further north than that of Scotland (which, of course, is where Hogwarts is located). The only area of Europe that fits that requirement is Scandinavia, which narrows down the possible countries to Norway, Sweden, Finland, and Russia.
Of those countries, only Norway is significantly mountainous (Russia, of course, has plenty of mountains too, but they aren’t in Europe). The CIA World Factbook describes the terrain of Norway as “glaciated; mostly high plateaus and rugged mountains broken by fertile valleys; small, scattered plains; coastline deeply indented by fjords; arctic tundra in north.” It has just the kind of scenic landscape Krum was describing for Hermione.
As for the ethnicity of Durmstrang students, in 1397 Norway was absorbed into a union with Denmark – a Germanic country – that lasted for four centuries, during which time Durmstrang would have been founded. This would make it at least 400 years younger than Hogwarts (which would make sense since Hogwarts is apparently the preeminent wizarding school of Europe, which implies it is the most established). Norway shares a small border with Russia, and since they also both have access to Barents Sea(!) transportation between the two countries would be relatively easy, accounting for the high representation of Slavs at Durmstrang.
Furthermore, Durmstrang is most likely located in the North-Eastern extremity of Norway. There is apparently a high non-Nordic population at Durmstrang, which indicates that it is probably located in an area that is relatively easy to access from other countries. Since it is so mountainous, transportation overland into the interior of Norway would be difficult. The North-East of the country has the advantage of bordering Sweden, Finland and Russia (all of which have smooth, rolling hills for easy overland travel), and, more importantly, is adjacent to Barents Sea, allowing for easy transportation between Norway and Russia. That the Durmstrang delegation arrived at Hogwarts by ship is, of course, further evidence that it has easy access to waterways. It is either right on the Barents Sea coast, or next to a fjord that feeds into Barents Sea.
So my big point is, Azkaban is on an island in Barents Sea, and Durmstrang is right next to Barents sea. This points to Durmstrang being a convenient base for Death Eater activity once they break out of Azkaban.