Since the Middle Ages, Jabłonna, a "healthy and quiet town", was part of the estate of the Płock bishops, who built a summer residence here in the 15th century. This was probably influenced by the scenic qualities and the short distance from Warsaw.
At the time, Jabłonna was famous for its apple orchards and honey from the forest huts.
In 1773, Jabłonna was bought by Michał Poniatowski, then Bishop of Płock, later Primate of Poland and younger brother of King Stanisław August.
In 1774, Michał Poniatowski commissioned the design of a new palace and park residence from Dominik Merlini, the first architect of the king and the Republic, who became famous for the expansion of the Royal Castle in Warsaw and the Łazienki Park.
The main element of the residence became a complex of three buildings: a central building with a flat for the owner, a left-hand two-storey pavilion called the Royal Pavilion, intended for King Stanisław August Poniatowski (now housing offices), and a right-hand pavilion intended for guests (now hotel guest rooms).
The building was erected in classicist style. Construction was completed in 1779.
Around the palace, in the place of the former baroque garden, an English landscape park was laid out in the 1870s and 1880s, overlooking the Vistula valley. The park's designer, Szymon Bogumił Zug, also constructed a number of park buildings, of which the following have survived to this day: a grotto, an orangery and a Chinese pavilion.
Jabłonna Palace is a very original residence - designed in the style of early classicism, with elements of rococo architecture. The centre of the composition was the round salon, much higher than the other rooms, where the stucco decorations were made by Antonio Bianchi in 1775 and the painting decorations by Szymon Mańkowski in 1777. It was entered through a rectangular vestibule (glazed hall), from which there was access to the left by a staircase to the tower and to the right to the antechamber (anteroom).
On either side of the living room were two rooms, the right of which housed the dining room and the left a conservatory. Flats consisting of bedrooms and dressing rooms were located in the extreme ends of the building. The ensemble of palace interiors also includes the rooms in the basement, which were used for social gatherings in summer (painted decoration 1776 - Antonio Tavelli). Today the basement houses the Palace Restaurant.
In 1794, Michal's nephew, Prince Józef Poniatowski, a Polish general, commander of the crown army of the Republic of Poland, Commander-in-Chief of the army of the Duchy of Warsaw, became heir to Jabłonna, who often visited here in 1798-1806. His personal flat was located on the ground floor of the right annexe.
After the tragic death of Prince Joseph at the Battle of Leipzig in 1813, Jabłonna was given to his sister Teresa Tyszkiewicz for life.
In 1822, the property became the property of Anna of Tyszkiewicz 1°voto Potocka 2°voto Dunin-Wąsowiczowa. Anna, who was a collector and talented draughtswoman, immediately set about transforming the property, wanting to make it a memorial to Prince Joseph.
It erected a triumphal arch with the inscription "To Poniatowski", collected mementos of him, and in time erected a plaque in the northern wall with the inscription "hero’s corner decorated carefully without disturbing the mementos I hand over to my descendants 1837/A.D.W.". Monuments and souvenirs, dedicated to national heroes and expressing patriotic feelings, were a special feature of Polish landscape parks at the time.
In 1827, a gate with two granite columns brought from the Teutonic Castle in Malbork was set up at the entrance to the park. Houses for doorkeepers were built at the gate. The houses bear the Latin greeting SALVE.
In 1837, the Palace was rebuilt according to the design of the architect Henryk Marconi. On both sides of the central part of the Palace, additional rooms were added: on the right - a dressing room and a bedroom, on the left - a cupboard and a corner room. The central part of the façade was segmented with Ionic pilasters, niches with decorative sculptures were made in the side wings, and iron verandas were put up on the park side. Inside, only the living room was not altered. The conservatory hall was rebuilt in moorish style. The bedroom and dressing room on the right were combined into a large library room. Outside, a columned pergola was added to the palace to the north and a lapidarium was installed.
Among the surviving sculptural fragments are a Roman medallion with the bust of Emperor Nerva, the first of the so-called five good emperors, and a relief depicting the bust of a bearded man, made in the 16th century by Baccio Bandinelli, a friend of Leonardo da Vinci.
Under Anna Dunin-Wąsowicz, the park was also transformed, with the trees formed into large flowerbeds and the courtyard in front of the palace planted with trees and shrubs.
New farm buildings and large stables with carriage houses were also built to a design by Henryk Marconi.
In 1944, the Palace was burnt down by German troops.
Jabłonna remained in the hands of the Potocki family until 1945.
The palace, which had been destroyed during the war effort and post-war looting, passed into the ownership of the State Treasury in 1946.
The Palace was reconstructed according to the design of Mieczysław Kuźma, while the park was reconstructed according to the design of Gerard Ciołek. During the reconstruction of the Palace, its central part was restored to its late 18th-century state, while the side parts were added in the first half of the 19th century, changing their elevations. The cast-iron decoration of the Moorish Hall was removed, restoring to it and to the other interiors its classicist character. The interior furnishings were completed after 1945 and the representative rooms were decorated with furniture and paintings from the late 18th century and the first half of the 19th century.
In 1953, the palace and its park were handed over to the Polish Academy of Sciences, which created a conference and leisure centre here: the House of Conventions and Conferences.