The Punjab princely states left forts and palaces: Qila Mubarak at Patiala, Qila Mubarak at Bathinda, Qila Mubarak at Faridkot, the Hira Mahal and old fort at Nabha, the Jagatjit Palace at Kapurthala, Moti Bagh at Patiala.
Qila Mubarak at Bathinda is the oldest, a brick mound fort claimed to date to the Kushan period and rebuilt many times. Razia Sultan, the only woman to rule the Delhi Sultanate, was imprisoned there in 1240.
Qila Mubarak at Patiala, begun by Baba Ala Singh in 1763, is a complex of palaces, courtyards and painted rooms. Its Darbar Hall museum holds arms attributed to Nadir Shah and to Guru Gobind Singh Ji, and a set of Bohemian cut-glass chandeliers that is the thing it is actually known for. The state medal collection is elsewhere, in the Sheesh Mahal at Moti Bagh.
Their condition varies from restored to collapsing. Ownership is split between state governments, archaeological authorities, private trusts and litigating families, and several have been the subject of long court cases.
The Faridkot estate litigation has run for over thirty years. Buildings do not survive court cases.
A qila mubarak is not one building. It is a walled compound holding a fort, a palace, a treasury, a darbar hall, quarters, stables, a shrine and a bazaar, built up over two centuries by successive rulers, so what stands inside the wall is a small town rather than a house.
Their fate after the merger was the same in each case: some rooms taken by government offices, some by schools, the rest closed. Maintenance passed to whichever department held the keys.
Nabha's is in poor condition and parts have come down. Faridkot's was tied up in estate litigation. Patiala's is under a long restoration. None of the four has a published condition survey.