The Treaty of Maastricht, signed in 1843 by Belgium and the Netherlands four years after the Treaty of London established Belgian independence,^[1] finally settled the border between the two countries.

Inability to decide a clear line of demarcation in Baarle-Hertog resulted in the division of the disputed territory into 5732 separate parcels of land.^[2] They formed part of a very complicated frontier, which sometimes passes through houses and has tiny enclaves^[3] because of land ownership dating back to the 12th century.^[4] A few of the Belgian enclaves within Dutch territory even have Dutch counter-enclaves within them.^[5]

Part of the left bank of the Meuse, near Maastricht, was returned to the Netherlands.^[6]

• Baarle-Hertog
• Treaty of London (1839)
• Iron Rhine and Iron Rhine Treaty of 1873
• Maastricht Treaty of the European Union