Currently there are 3 claimants to the title prince of Orange (or princess of Orange). In the past there even have been 4.
1. In the Kingdom of the Netherlands, the title is traditionally borne by the heir apparent of the Dutch monarch. Originally only worn by men, since 1983 the title descends via absolute primogeniture, which means that the holder can be either Prince or Princess of Orange. The dynasty of Orange-Nassau was established as a result of the marriage of Hendrik III of Nassau-Breda from Germany and Claudia of Châlon-Orange from French Burgundy in 1515. Their son René inherited in 1530 the independent and sovereign Principality of Orange from his mother's brother, Philibert of Châlon. After the death of René in 1544, his cousin Willem of Nassau-Dillenburg inherited all of his lands. This "Willem I of Orange", in English better known as William the Silent (in Dutch also Willem de Zwijger), became the founder of the House of Orange-Nassau.
Current holder: princess (Catharina-)Amalia of the Netherlands
https://en.wikipedia.org/...malia,_Princess_of_Orange2. After William III of England (Stadthouder Willem III van Oranje, male line descendant of Willem the Silent) died without children, a dispute arose between Johan Willem Friso and Friedrich I of Prussia, which was settled in the Treaty of Partition (1732); consequently, Friso's son, Willem IV had to share use of the title "Prince of Orange" (which had accumulated prestige in the Netherlands and throughout the Protestant world) with Friedrich Wilhelm I of Prussia. Friedrich Wilhelm I of Prussia ceded the Principality of Orange to King Louis XIV of France (while retaining the title as part of his dynastic titulature).
William III and Mary II had no legitimate children.
An agnatic relative of William III, Johan Willem Friso of Nassau, who was also cognatically descended from William the Silent, was designated the heir to the princes of Orange in the Netherlands by the last will of William III. After William III's death in 1702, his heir in the low countries was Johan Willem Friso of Nassau Diez. He was the son of Hendrik Casimir II, Prince of Nassau-Dietz, and Princess Henriëtte Amalia of Anhalt-Dessau who were both first cousins of William III (both were offspring of a daughter of prince Frederik Hendrik, while William III descended from Frederik Hendriks only surviving legitimate son Willem II). They did however have a claim, albeit distant, to the principality itself due to Johan Willem Friso's descent from Louise de Coligny, who was a descendant of the original Princes of Orange. (Louise's great grandmother, Anne Pot, Countess of St. Pol, was a descendant of Tiburge d'Orange, who married into the des Baux family). They could also claim descent from the del Balzo, an Italian branch of the des Baux family, via the marriage of Princess Anne to Willem IV, Prince of Orange. Anne was the eldest daughter of George II of Great Britain, who was a descendant of Elizabeth Woodville, wife of Edward IV of England. Elizabeth Woodwille's grandmother was Margherita del Balzo, another descendant of Tiburge d'Orange. They also claimed on the basis of the testament of Filip Willem, Maurice and Willem III. Finally, they claimed on the basis that Orange was an independent state whose sovereign had the right to assign his succession according to his will. France never recognized any of this, nor allowed the Orange-Nassaus or the Hohenzollerns to obtain anything of the principality itself
Friedrich I of Prussia (1702–1713), a senior descendant in female line from Willem the Silent, He was the third son of Friedrich Wilhelm, Elector of Brandenburg by his father's first marriage to Louise Henriette of Orange-Nassau, eldest daughter of Frederik Hendrik, Prince of Orange. So he was also a first cousin of William III. Because William III died without legitimate children, the principality was regarded as having been inherited by his closest cognate relative on the basis of the testament of Frederik Hendrik, Friedrich I of Prussia, who ceded the principality — at least the lands, but not the formal title — to France in 1713 France supported his claim. In this way, the territory of the principality lost its feudal and secular privileges and became a part of France. The Treaty of Utrecht allowed the King of Prussia to erect part of the duchy of Gelderland into a new Principality of Orange. The kings of Prussia and the German emperors styled themselves Princes of Orange till 1918.
Current holder: Georg Friedrich Ferdinand Prinz von Preußen (= Georg Friedrich Ferdinand, Prince of Prussia)
https://en.wikipedia.org/...edrich,_Prince_of_Prussia3. Louis de Mailly, Marquis de Nesle et de Mailly, appointed by the French king, and his descendants, descended through another line of the house of Chalons-Arlay. In 1673, the absolute royal ruler of France, King Louis XIV - "L'état, c'est Moi" - (the State, that is me!) determined the government of the Principality of Orange to be given to the Marquis, as being a pretendent closest to Prince Willem III of the Netherlands. This as revenge for the war that both had. Fun fact: Louis de Mailly only had 5 (surviving) daughters of which 4 became a favorite aka a mistress of king Louis XV (grandson of previously mentioned Louis XIV).
As Louis only had daughters, his nephew Louis de Mailly (1744-1810) claimed the title on his turn, but had only one daughter (who married Louis d'Arenberg, with a daughter Amélie, wife of Pius Duke in Bavaria). Eldest ancestor Humbert Lord of Mailly-sur-Saône (+ 1029), son of Gauthier, was mentioned as Count of Dijon in 1007. His descendant Jean de Mailly (ca. 1405-after 1468) was the first to carry the title Baron. Louis Charles de Mailly, Marquis de Nesle, of the elder line of Jean´s descendants, married Jeanne de Monchy, who would bring the Orange-claim into the family. Their grandson was Louis de Mailly, Marquis de Nesle (1689-1764). A descendant of the younger line of Baron Jean, marshall Augustin Joseph de Mailly (1708-1794), was created Comte de Mailly and Marquis d'Haucourt in January 1744. His son Adrien de Mailly (1792-1878) claimed the title Prince d'Orange, although he did not descend from the Châlon family. His descendants still use the title.
Current holder: Guy, Marquis de Nesle et de Mailly, Prince d'Orange.
4. Louis Armand II, Prince of Conti (Bourbon), appointed by the French king, and his descendants, the Princes of Conti becoming extinct in 1815.
