Yinchuan, a city in Ningxia Hui Autonomous Region, China, is located approximately 140 kilometers (87 miles) west-northwest of Hengshui, a city in Hebei Province. The direction from Yinchuan to Hengshui is predominantly in a west-northwest direction. This orientation is influenced by the geographical layout of the region, with the Yellow River forming a natural boundary between Ningxia and Hebei, and the terrain gradually sloping from the highlands of Ningxia towards the plains of Hengshui.

The west-northwest direction is evident when examining the compass headings. Yinchuan is situated at approximately 38.47°N latitude and 106.27°E longitude, while Hengshui is at around 38.47°N latitude and 115.03°E longitude. The difference in longitude suggests a westward direction, and the slight difference in latitude indicates a northward component. According to the Great Circle Distance Calculator, the shortest distance between the two cities is approximately 140 kilometers, which aligns with the west-northwest direction.

This direction is also supported by historical and cultural factors. The Silk Road, an ancient network of trade routes connecting the East and West, passed through the region, and the trade routes followed natural geographical features, such as rivers and mountains. The west-northwest direction from Yinchuan to Hengshui would have been a logical route for merchants and travelers moving along the Silk Road.

Furthermore, the transportation infrastructure in the region reflects the west-northwest direction. The G6 Beijing–Shanghai Expressway, one of China's major national highways, runs in a west-northwest direction, connecting Yinchuan and Hengshui. This highway is a key component of China's national road network and facilitates the movement of goods and people between the two cities.

In conclusion, Yinchuan is located in a west-northwest direction relative to Hengshui, influenced by geographical, historical, and cultural factors. The alignment of the Great Circle Distance and the transportation infrastructure, such as the G6 Expressway, further supports this direction.