Afghan-Pakistani Border map

Pakistan: The South Waziristan Migration
Stratfor Global Security and Intelligence Report

Contrary to popular perception, the area along the Afghan-Pakistani border is fairly heavily populated. The terrain is extremely rugged, but there are millions of Pakistanis living in [Pakistan’s] FATA [Federally Administered Tribal Areas], and many of them are extremely conservative and hostile toward the Pakistani government. This hostile human terrain poses perhaps a more significant obstacle to the Pakistani military’s operations to root out jihadists than the physical terrain. Accurate and current population numbers are hard to obtain, but the government of Pakistan estimated the population of South Waziristan to be nearly 500,000 in 1998, although it is believed to be much larger than that today. There are also an estimated 1.7 million Afghan refugees living on the Pakistani side of the border.