Covering an area in which you can fit in fourSwitzerlands with still some more room, but with a population of just over 6 million, Eastern Anatolia is all about lonely and vast landscapes of mountainous terrain, with occasional flat-ish plateau inflitrated inbetween.
While the daytime temperatures of around 30°C—yet it can easily hit 40°C or more in relatively lower western parts of the region around Malatya, though—in summer make travelling in Eastern Anatolia a breeze (especially if you have arrived from the much hotter regions of Southern and Southeastern Turkey), the nights are fairly chilly and it's common for temperatures to go down as low as +12°C in late evenings, even in the hottest month of August, so pack along at least a cardigan or sweater.
Eastern Anatolia is constantly under snowcover during winter, which even shuts some non-major roads for days on end, and temperature can drop as low as a whopping -40°C — warm clothing is more essential than ever.
In the eastern and southeastern areas (near Iranian border and around Lake Van) of the region, the mother tongue of most locals is Kurdish. However most locals, especially younger ones, are also bilingual in Turkish, although heavily accented in most cases.
Local Turkish dialect spoken in northeastern section of the region (around Erzurum, and Kars) is far from the standard Turkish based on Istanbul dialect and is very close to Azerbaijani spoken in the neigbouring country (to the point of being virtually identical in the easternmost parts of the region, around Iğdır close to the border with Nakhchivan), although the written word always uses standard Turkish orthography as is usual.
Zaza, another Indo-Iranian language closely related to Kurdish, may also be heard in certain locales, especially in the central parts of the region around Tunceli and Bingöl.
As in Southeastern Anatolia, it is important to be cautious with whom you are smattering Kurdish or Zaza. Trying to strike up a conversation in those languages with a Turkish official, especially one from military, can have dire consequences.
Erzurum is the main gateway to the region with fairly frequent air, bus, and rail connections with the rest of the country. Other secondary-major cities with airports include Malatya, and Van, both of which also has rail links with the rest of the country, and with Iran in the case of Van. Occasionally potholed (but getting better and wider day by day) highways connect the region to other Turkish regions in north, south, and west; and to Iran to east.
Most towns and cities in the region are 1,500 mt above the sea elevation (a fair number of which are close to 2,000 mt), and it's not uncommon for mountains—some of which are popular sights in themselves—to rise more than 3,000 mt, so make sure to take usual precautions against altitude sickness.
Those that had enough with the chilly mountain air can head south to much warmer (and, indeed, semi-desert) Southeastern Anatolia. If you prefer to have a glimpse of sea after poking about inland regions, though, you are much better heading north to Eastern Karadeniz, the nearest stretch of coastline backed by lush and misty mountains, although much of region's beaches were lost to coastal highway. Travellers heading for major centres of western Turkey will traverse Central Anatolia to west, while those intending to do the overland route to India can cross the border into Iran to east from a number of border crossings, which are located east of Doğubeyazıt, Van, and Hakkari north to south. Just north of Iran is Azerbaijan's Nakhchivan exclave, with a border crossing from east of Iğdır. There is also a crossing on the Georgian border to north, Türkgözü north of Kars/Ardahan. Although much less crowded than Sarp crossing on the Black Sea coast, it isn't any faster to cross the border there, as, for once, it's much remoter and harder to get a direct transportation to from major centres, and secondly it seems border formalities take longer to finish. If Armenian ruins all over Eastern Anatolia aroused an interest, Armenia to east across the border awaits, although that would require a detour via Iran or Georgia (which has much less complicated visa issues) as the border is currently closed.