(covers information from several alternate timelines)
Europe, including the Netherlands
The Netherlands was a country on Earth located on the continent of Europe. The people of the Netherlands were known as the Dutch. The Netherlands flag was three horizontal bands of red, white, and blue. (ENT: "First Flight") Its neighbor countries at times have been Germany, Belgium, France, and across the channel, Old Britain.
Important people from the Netherlands were 17th century philosopher Benedict de Spinoza who wrote The Ethics, (TOS: "Where No Man Has Gone Before") and the 19th century painters Vincent van Gogh, (TNG: "The Most Toys"; DS9: "Second Sight") and Johannes Vermeer, who made paintings like The Concert. (VOY: "The Killing Game")
Aside from its contributions to the arts in this era, the Netherlands was also significant player in Earth's Age of Exploration, a fact acknowledged in the Star Trek: Enterprise opening credits which had a Dutch language map which showed several islands by their original names as given by explorer Jacob Roggeveen, and another map in which Australia is called "Nova Hollandia".
In 2032, the Netherlands took part in the Ares IV mission. (VOY: "One Small Step")
The Dutch flag could be seen on the Ares IV model amongst others.
In a Borg-created alternate timeline, a large area of the Netherlands was flooded in April 2063, as was witnessed by the crew of the USS Enterprise-E when they flew over the country. (Star Trek: First Contact)
In 2143, the Ariane 1 assignment patch, which was on display in the 602 Club, bore the flag of ESA member Netherlands. (ENT: "First Flight")
In the non-canon Star Trek Fact Files, Netherlands was a member of the International Space Agency in the early 21st century.
In another alternate timeline, this time created by Vosk and the Na'kuhl, Vladimir Lenin had been assassinated in 1916 and Russia had never become communist. Adolf Hitler therefore "quickly took England", being able to keep his focus on the West after the successful occupation of France, Belgium, and the Netherlands. (ENT: "Storm Front, Part II")
France, Belgium, and the Netherlands being overrun by Germany's armed forces was a fate shared in both reality as well as in the alternate timeline. The Netherlands was actually the first to fall on 14 May 1940, pursuant a Luftwaffe terror bombardment on its second largest city, Rotterdam, a mere five days after the German offensive in the West had begun.