The city was formerly known as Ganzhou, named after the sweet waters of its oasis. The name is retained by both Zhangye's central district and province. The name appears in Marco Polo's Travels under the name Campichu.
Zhangye was used as the name of the area's commandery and then for the city itself. The name Zhangye ("Extending Arm") is excerpted from the phrase "To extend the arm of the country through to the Western Realm" (张国臂掖，以通西域).
Zhangye lies in the center of the Hexi Corridor. The area is on the frontier of China Proper, protecting it from the nomads of the northwest and permitting its armies access to the Tarim Basin. During the Han Dynasty, Chinese armies were often engaged against the Xiongnu in this area. It was also an important outpost on the Silk Road. Before being overrun by the Mongols, it was dominated by the Western Xia, and before by the Uyghurs from at least the early 10th century. Its relation to the larger Uyghur state of Qocho is obscure, but it may have been a vassal.
The Mongol Emperor Kublai Khan is said to have been born in the Dafo Temple, Zhangye, now the site of the longest wooden reclining Buddha in China. Marco Polo's journal states that he spent a year in the town during his journey to China.
The pine forests of the Babao Mountains (part of the Qilian range) formerly regulated the flow of the Ruo or Hei Shui, Ganzhou's primary river. By ensuring that the meltwaters lasted throughout the summer, they avoided both early flood and later drought for the valley's farmers. Despite reports that they should thus be protected in perpetuity, an imperial official in charge of erecting the poles for China's telegraph network ordered them cleared in the 1880s. Almost immediately, the region became prone to flooding in the summer and draught in the autumn, arousing local resentment.
Christian missionaries arrived in 1879, after Suzhou was found to be too hostile for their settlement.
Zhangye has 1 urban district, 4 counties, 1 autonomous county, 97 towns, and 978 villages.
Zhangye is located in central Gansu along the Hexi Corridor, occupying 42,000 km2 (16,000 sq mi). It takes up the entire breadth of the province, running from Inner Mongolia on the north to Qinghai on the south, but its urban core is at Ganzhou in the oasis formed by the Ruo or Hei River. Its streams, sunlight, and fertile soil make it an important regional agricultural center, although it was seriously damaged by overforesting in the 19th century.
The Zhangye Danxia National Geological Park, covering an area of 510 square kilometers (200 sq mi), is located in Linze and Sunan counties of Zhangye, 30 kilometers (19 mi) west of the city center. Known for its colorful rock formations, it has been voted by Chinese media outlets as one of the most beautiful landforms in China.
Zhangye has a cold desert climate (Köppen BWk) with very warm summers and cold and very dry winters. The monthly 24-hour average temperature ranges from −9.2 °C (15.4 °F) in January to 21.5 °C (70.7 °F) in July. The mean annual temperature is 7.31 °C (45.2 °F), while annual rainfall is 130 millimeters (5.1 in), almost all of which falls from May to September. The winters are so dry that snow is extremely rare.
Zhangye has a total population of 1,199,515, only 260,000 being urban residents. There are 26 ethnic minorities other than Han represented including many Hui, Yugur and Tibetans.
Zhangye is served by China National Highways numbers G30 Expressway, 227 and 312.
Zhangye Railway Station is on the Lanzhou–Xinjiang Railway, located to the north east of the city. A high speed railway station has been constructed on the south west side of the city, Zhangye West Railway Station was opened on the 26th of December, 2014 as part of the Lanzhou–Ürümqi High-Speed Railway.
Zhangye Ganzhou Airport, a combined civilian-military airport, opened in October 2011 with flights to Lanzhou and Xi'an.
The 2002 GDP was 7.566 billion RMB, almost 9% growth over the previous year. Annual urban income was 5960 RMB,10.4% growth from the previous year and rural income was 3092 RMB, up 5%.
Hexi University (河西学院) is located in Zhangye. Approximately 10,000 students are enrolled at the university.
Zhangye has hosted a round of the Chinese Rally Championship (CRC) since 2011. Held on specially constructed roads across the deserts north and to the south of the city. The event attracts over 100 entries regularly, including international foreign drivers. A stadium for side-by-side super special stages has also been constructed.