The capital of The Netherlands (or Holland) is Amsterdam. The Hague has been the administrative centre and belonged to the richest of Holland since 1230. In 1558 the government also moved there - I am guessing that this was because all the systems of control were already in place. This information is from Wikipedia though so you may want to check it. The following is also from there "After the Napoleonic Wars, Belgium and the Netherlands were combined in the United Kingdom of the Netherlands to form a buffer against France. As a compromise, Brussels and Amsterdam alternated as capital every two years, with the government remaining in The Hague. After the separation of Belgium in 1830, Amsterdam remained the capital of the Netherlands, while the government was situated in The Hague". Therefore it is for historical security and control reasons. The website also says that the Hague was where the first international peace conference was held and has become the international city of peace. I guess that this was thought most suitable for the International Tribunal - which was built to provide investigation and justice for the world's greatest crimes against humanity and peace.

officially the capital of Netherlands is Den Haag. i am not sure about the division, but it is true that not every official office is in the hague. you should get an answer from a dutch to explain this well. but, maybe this helps you with your doubts: the more dynamic cities of nederlands are Amsterdam, Rotterdam, Den Haag, Utrecht.they are separated by not much distance and you can reach one of them from the other in less than half an hour, and in the middle of the rectangle (approximately) they form is situated the int'l airport. so, moving between cities is less difficult than for some people in other parts of the world to go to the center of town. and public transportation in this area is amazingly efficient.