While most if not all of the Chinese dishes I've posted about so far come from central/southern/eastern China, there is also some very good food to be had in other areas. Later this week, I'll be discussing a dish from Xinjiang, an autonomous region in the northwest of China, so I thought today I'd give some brief background on the region.
China is a huge country, with many different types of terrain and climate. Although it has a coastline of 14,500 km (9,000 miles) (source: CIA World Factbook), even a relatively central province such as Sichuan is 725 km (450 miles) from the sea at its very closest point, and 1,600 km (1,000 miles) at its furthest (source: Google Maps geocoding). Xinjiang, which borders on countries such as Kazakhstan and Mongolia, is even further away from the sea. In addition to the map above, Wikimedia Commons has a map of China which may help give some perspective on all this.
The vast majority of the land in Xinjiang is uninhabited desert; the population is found in the mountains and in oases around the edges of the deserts. The staple food is not rice, but wheat products such as bread and noodles. Commonly-used flavourings include cumin and other fragrant spices.
Xinjiang has a significant Muslim population, so you won't find the predominance of pork dishes here that you would in other Chinese cuisines [see footnote]. Instead, the main food animals are sheep and goats, though other animals such as chickens are also eaten. Typical dishes include laghman (handpulled noodles with a lamb-based sauce), big-plate chicken (a stew of chicken and potatoes), flatbreads, lamb grilled on skewers, and samsa (lamb-stuffed pastries similar to samosas). Rice is reserved for festive dishes such as pulao, a dish based on rice flavoured with meat and vegetables.
According to Wikipedia, the majority population of Xinjiang at the 2000 census was Uyghur (sometimes spelt "Uighur"), with Han Chinese coming a close second. Hence, while Mandarin is widely used in Xinjiang, so is the Uyghur language, which is a Turkic language (as opposed to the Sino-Tibetan Mandarin) written in an alphabet derived from Arabic. Here's an example of a menu from Xinjiang written in Chinese, English, and Uyghur. For the same reason, you may see the food of the region referred to as Xinjiang food (新疆菜/Xīnjiāng cài), Uyghur food, or sometimes Chinese Muslim food (though the latter is a broader term).
Uyghur food is not found only within Xinjiang; according to Beyond the Great Wall by Jeffrey Alford and Naomi Dugiud, Uyghur restaurants and street food stalls are common in central China, and pinetree notes in comments that in fact Xinjiang food is now found all over China. Even London now has a Xinjiang restaurant — Silk Road in Camberwell.
Footnote:  Indeed, while in most regions of China the character 肉 (ròu, literally "meat") is taken in the absence of further qualification to mean pork, you can't necessarily assume that this is the case on a Xinjiang menu; here's a photo of part of the menu at Silk Road, which simply uses 肉 to indicate a lamb dish, rather than 羊肉 (yáng ròu/sheep/lamb). I'm not entirely sure how widespread this practice is, however.