Belgium–Netherlands border

The Hague Treaty delimited the border in general terms while the Maastricht Convention delineated the boundary with detailed descriptions and maps on a 1:10,000 or, where necessary, 1:2,500 scale.

[1] While the two treaties resulted in the finalisation and demarcation of the main border between the two countries, it left the complicated territorial situation in Baarle unresolved.

The current Belgian enclaves as well as Dutch counter-enclaves which has resulted in what has been called the world's most complicated international boundary,[2] is a continuation of land ownership from the feudal age.

During World War I, an electric fence was installed along the border by the German Army, called the Wire of Death.

On 1 January 2018, a border realignment together with a corresponding territorial swap between Belgium and the Netherlands took place along the Meuse River near Eijsden in Limburg Province.

[4] The territorial swap saw Belgium giving a total of 16.37 hectares (40.45 acres) of land to the Netherlands comprising two uninhabited riverine peninsulas, previously cut off from "mainland" Belgium by Dutch territory, known as Presqu’île de L’llal and Presqu’île d’Eijsden.

In return, the Netherlands gave Presqu’île Petit-Gravier which was 3.08 hectares (7.63 acres) in size, to Belgium.