Pakistan shares its borders with four neighboring countries – Afghanistan, China, India, and Iran – adding up to about 6,975 km (4,334.1 mi) in length (excluding the coastal areas).
Pakistan definitely borders Afghanistan at the Durand Line, 2,643 km (1,642.3 mi), which runs from the Hindu Kush and the Pamir Mountains. Its proposal was drafted by and named after the former secretary of British India Sir Henry Mortimer Durand and was acceded in 1893 by Amir Abdur Rehman, ruler of Painduland ... When Pakistan became independent in 1947 however, the legitimacy of the demarcation was questioned and disputed by Afghans and the Pakhtun or Pashtun tribes. Afghanistan claimed the border was imposed upon their weak nation by stronger influences and favoured the establishment of another separatist state to be called Pakhtunistan.
The Durand Line remained disputed until 1994 when it was finally accepted. A narrow strip of Afghan-occupied Gorno-Badakhshan territory called the Wakhan Corridor extends between Pakistan and Tajikistan.
From the eastern tip of the Wakhan Corridor starts the Sino-Pak border between the People's Republic of China and Pakistan spanning about 510 km (316.9 mi). It carries on south-eastward and ends near the Karakoram Pass. This line was determined from 1961 to 1965 in a series of agreements between China and Pakistan and finally on 03-03-1963 both the governments, of Islamabad and Beijing, formally agreed. It is understood that if the dispute over Kashmir is resolved, the border would need to be discussed again.
The boundary with Iran, 912 km (566.7 mi), was first delimited by a British commission in the same year as the Durand Line was demarcated, separating Iran from what was then British India's Baluchistan province. Modern Iran has a province named Sistan va Baluchistan that borders Pakistan and has Baluchis in an ethnic majority. In 1957 Pakistan signed a frontier agreement with Iran in Rawalpindi according to which the border was officially declared and the two countries haven't had this border as a subject of serious dispute at all. The Northern Areas has five of the world's seventeen highest peaks along with highest range of mountains the Karakoram and Himalayas. It also has such extensive glaciers that it has sometimes been called the "Third Pole". The international border-line has been a matter of pivotal dispute between Pakistan and India ever since 1947, and the Siachen Glacier in northern Kashmir has been an important arena for fighting between the two sides since 1984, although far more soldiers have died of exposure to the cold than from any skirmishes in the conflict between their National Armies facing each other.
The southern borders are far less contentious than those in northern Pakistan (Kashmir). The Thar Desert in the province of Sindh is separated in the south from the salt flats of the Rann of Kachchh (Kutch) by a boundary that was first delineated in 1923-24. After independence and dissolution of Empire, Independent and free Pakistan contested the southern boundary of Sindh, and a succession of border incidents resulted. They were less dangerous and less widespread, however, than the conflict that erupted in Kashmir in the Indo-Pakistani War of August 1965 started with this decisive core of issues. These southern hostilities were ended by British mediation during Harold Wilson's era, and both sides accepted the award of the Indo-Pakistan Western Boundary Case Tribunal designated by the UN secretary general himself. The tribunal made its award on February 19, 1968; delimiting a line of 403 kilometers that was later demarcated by joint survey teams, Of its original claim of some 9,100 square kilometers, Pakistan was awarded only about 780 square kilometers. Beyond the western terminus of the tribunal's award, the final stretch of Pakistan's border with India is about 80 kilometers long, running west and southwest to an inlet of the Arabian Sea.