Venezuela ’s acting President Delcy Rodríguez arrived in the Netherlands on Sunday where she will defend her country's claim to a mineral- and oil-rich region in western Guyana before the United Nations highest court in a dispute that has spanned decades.

The International Court of Justice in The Hague is holding a series of hearings with the South American neighbors which both claim ownership of Essequibo — a territory of nearly 62,000 square miles rich in gold, diamonds, timber and other natural resources, located near massive offshore oil deposits.

Venezuela has considered Essequibo its own since the Spanish colonial period, when the jungle region fell within its boundaries.…