The Siachen Glacier is part of a larger territory dispute between India and Pakistan. Both India and Pakistan have had a significant military presence here (mostly along the Saltoro Ridge) since April 1984. The conflict has been called, The Highest Battleground in the World". Pakistan and India spend upwards of $1 million dollars a day to keep troops amassed along such demanding and inhospitable terrain.
The strangeness of the border is largely due to the history of the conflict with an important contributing role by the USA. The majority of the border between India and Pakistan in Kashmir is defined by what is known as the "Line of Control"... essentially the cease fire line that was negotiated and agreed to by both sides. The Line of Control is the dashed line in the lower left area of the map. In that agreement the border extended only to a point known as NJ9842 (shown on the map). The geography north of that point was considered too mountainous, cold and inhospitable to be of interest to either party. So the agreement fixed the NJ9842 point and then added the clause, "and thence north to the glaciers". This description actually worked for many years because the area was of little strategic interest. Sometime in the 1980s, the US military created a map of the area that continued the border all the way to the Karakoram Pass. This effectively gave the otherwise unclaimed territory to Pakistan. Around the same time, Pakistan had also started to grant climbing permits to K2, the Himilayan mountain known as the hardest mountain to climb. When the Indian Army learned of this, they immediately assembled a military expedition to the Siachen Glacier. The glacier and the surrounding mountains range from 19,000 to 22,000 feet above sea level. The whole area is extremely cold and heavily glaciated. It is sometimes called The Third Pole. Never-the-less both Pakistani and Indian troops have chosen to remain amassed along the Saltoro Ridge.
Most conflicts seem to start when one party draws a border that another doesn't like. In this case, It was the absence of a clear border that started all the fuss. Both India and Pakistan realize that the standoff is an exercise in futility and hope to end it. There have been discussions between the two countries but none have proven successful.