The settlement of Opitołoki was first mentioned in 1371 in the chronicle of Hermann von Wartberge. A manor house in the village is also mentioned from the 15th century onwards. Mention of it appears in the 16th century. It is also known that in the 17th century, the Samogitian judge and Ejragol civil servant (supervisor of serfs) Piotr Szukszta built the first brick palace in Opitołoki.

In 1587-1741 the local estate was in the hands of the Szukszta family, later it was taken over by the Zawisza and Karpi families, and then the estate was divided between the Tyszkiewicz and Zabiełłoło families. Perhaps, as Roman Aftanazy writes, Szymon Zabiełło married Barbara Zawiszanka, and thanks to this marriage the estate went to the Zabiełłos. He also mentions that according to the "family tradition of the last owners, this estate was supposed to have belonged to the Kobylinskis in the mid-19th century. The grandfather of the last owner, Karol Zabiełło (born in 1809), was married to Matylda Kobylińska". In the second half of the 19th century the Zabiełłos united both estates in their hands. The last owner of Opitolok was Karol Zabiełło (1868-1937), son of Henryk from Łabunów and Jadwiga Komar, who lived there until World War II.

From the 'Dictionary of Geography and Other Slavic Countries' we learn that before 1886 there was a 'brick palace in a beautiful park'. At the time, the estate and palace belonged to Count (he obtained the title in 1887) Henryk Onufry Maria Zabiełło (1844-1900), residing permanently in Łabunów. It was for Łabunowo that a design for a new palace was drawn up in 1882 by the architect Karol Kozłowski, designer of the National Philharmonic in Warsaw and theatres in Minsk and Lublin, among others. He may also have designed the palaces at both estates for the same owner. Around 1900, the residence was probably reconstructed, to be done by an unknown architect from Riga. The reconstruction designs were made by the owner, Karol Henryk (son of Henryk Onufry) Zabiełło.

The last heir of Opitolok was Czeslav Zabiełło (1900-1942). He was arrested by the NKVD in 1940 and sent to Siberia, where he died after two years. His youngest brother Karol died of typhoid fever in 1944, the other two: Władysław and Zygmunt remained in Lithuania after 1945. The former died in Kaunas in 1966, and the latter lived in Panevėžys and passed away there in 1993.

The Opitolotsk Palace is a two-storey building, built on a rectangular plan. Its much lower ground floor was used for residential or household purposes, while the ground floor had representative functions.

The front elevation is decorated with three symmetrically arranged risalits. The central, less projecting one is preceded by a portico with four Doric columns and two rusticated columns at the corners, which carry a balcony. The second storey of the central risalit, pierced by three porte-phenetres, is segmented by pilasters and corner rustications, decorated with coat-of-arms shields and closed by a balustrade with sculptures. The three-storey side risalits - with two rectangular windows on the ground floor, a semicircular closed porte-phenetre with a balcony and two narrow windows on the sides on the first floor and a large semicircular window on the second floor - are decorated with panels, pilasters, cornices, window pediments, busts on consoles, stucco and bonia.

At the two side elevations on the ground floor there were small vestibules with balconies above. Very modest treatment was given to the garden elevation.

The central risalit once housed a representative grand hall. The side parts of the palace, with rooms of different shapes, had a two-bay layout, divided by corridors. The left side was used for domestic purposes, while the right side housed the guest rooms and the owner's study and bedroom. Both side sections had smaller staircases with wooden steps. On the first floor of the central part was the main staircase, and in the middle was a gallery from which one entered the large living room. There was a library, bedrooms, a lounge and a dining room.

The formal rooms had ceilings decorated with stucco and patterned floors. The lower part of the walls of the dining room was covered with oak panelling. In addition to decorative cookers, the grand salon and library also had fireplaces. The hall was decorated with hunting trophies and a collection of old weapons. A large stuffed bear stood at the door. Roman Aftanazy, thanks to his correspondence with the widow of the last owner of Opitolok - Jadwiga Zabiełłowa, obtained information about the palace's furnishings:

"[...] The movable equipment of the hall consisted of chairs made of elk horns, lined with soft cushions. The grand salon as a whole, thus including the furniture, was in the Louis XV style. The adjoining lounge had furniture original to the Jacob style with bronzes. All the salons and some other rooms were decorated with paintings - and considered to be very valuable - miniatures, which were collected in large numbers in Opitoles. Only one of these, a French one, eventually found its way into the collection of the National Museum in Warsaw. In the dining room, with furniture made of dark oak, family portraits hung above the panelling. On a shelf enclosing the wainscoting was set antique European porcelain and old silver. Some of the porcelain in the form of plates hung on the walls. Around the library room were glassed-in cupboards, also made of dark oak, containing what was probably several thousand books, mainly in Polish, French and German. The library also housed the Zabiełło family archive. There were also some valuable bronzes in the palace collection."

A set of horn furniture, which won a gold medal at the Paris World Exhibition in 1900, was transported by rail to Kaunas by the then owner Henrik Zabello for one and a half kilograms of gold and placed in three rooms of the palace.

In 1947, when the Opitolotsk estate was nationalised, it was possible to collect and preserve some of this unique furniture. They are now exhibited in the Regional Museum in Kėdainiai, and several armchairs were found in Trakai Castle. The palace, salvaged with all its memorabilia and collections during World War I, was blown up by the retreating Germans in 1944. The interior furnishings were already lost in 1940. Only the wooden staircase, fragments of old cookers and some windows have survived.

The landscape park of about 10 hectares, landscape type, was established in 1819 and extended in the middle of the 19th century, full of old trees, with numerous avenues and ponds. The palace stood on a hill, the rear, eastern part of the garden falling into a ravine and the Alkupis river. In the area of the park, it joined the Niewiaža River. A significant part of the park was also located on the other bank opposite the palace hill.

There were two entrances to the palace grounds. The shorter one from the front - the main entrance gate stood on the axis of the palace. In front of the building was a gazebo, the centre of which was occupied by a flower bed with a water feature and a stone statue of a boy with an ibis. A second entrance crossed the back part of the park and the river with a bridge and lions lying on its sides. Open glades were also part of the garden - trees were planted in groups to emphasise their picturesqueness and open up the view of the countryside.

In 1954, the palace was rebuilt and used as an old people's home, later housing a psychoneurological boarding school. In autumn 2007, the hospital moved to the other side of the Niewiaža River. The palace underwent a minor renovation in 1990. In 1998, one of the outbuildings was demolished. In 2018, the district municipality signed a contract with a private entrepreneur and, under this agreement, handed over the management and use of the palace for a period of twenty years. In 2020, the contract was terminated. No work had started by then. In September 2022, a fire broke out in the palace, burning the interior, ceiling, walls and roof.

The palace and park are currently deteriorating, and it was one of the most impressive and beautiful palaces in the Niewiaza valley.