The last private owners of Łańcut (from 1816 to 1945) were the Potocki family. Alfred I Potocki (1786-1862) converted the property into an entailed estate, averting its fragmentation. Alfred II (1822-1889) paid the residence little attention, spending most of his time in Vienna and Lvov (one of his titles was Viceroy of Galicia). His neglect was made up for by Roman (1851-1915), who initiated the final episode of modernisation (1889-1912). The palace was remodelled in Eclectic style, historic rooms being treated with due respect, to a design by the French architects Armand Bauque and Alberto Pio. In 1890-1904 an extensive landscape park was created beyond the fortifications. An Italian garden, a rose garden, an orchid house and a palm house were also founded. Of all the park buildings the most important is that built in 1902 to serve as a stable and coach house, which currently boasts a unique collection of carriages. The former carriage-horse stables today house an exhibition of Eastern Orthodox church art. Alfred III (1886-1958), an exemplary cosmopolitan, was one of the wealthiest men in Europe. As the outcome of the Second World War grew increasingly apparent, he sent several hundred crates to Vienna containing the palace’s most valuable works of art (paintings by Bellini, Boucher, Fragonard and Watteau; tapestries, family porcelain and silver), and left the castle himself barely a week before the arrival of the Soviet army. The palace was saved from plunder by its servants.

The interiors (containing vast collections of art, weapons and artistic handicrafts, as well as a magnificent library), untouched by the devastation of the last war, attract multitudes of tourists. As well as lavish reception halls there is also a series of rooms of various function representing a variety of periods. These include the Chinese Suite, the Pompeian Drawing Room, the Mirrored Study, the Winter Dining Room, and the Yellow Bathroom, to name but a few. The series of reception rooms on the first floor leave a lasting impression: the Billiard Room, the Dining Room above the Gate, the Ballroom and the Grand Dinging Room, all designed by Aigner. The library and the Neo-Classicist Columned Hall are also worth a look, the latter being adorned with a statue of Eros by Antonio Canovy dating from 1787 (a sculpted portrait of the young Henryk Lubomirski).

Łańcut offers an ideal example of the transformation of a building from a fortified castle into an open residential palace, which retains virtually all of its high quality furnishings - a rare occurrence in Poland.