The Punjab State Archives at Patiala hold the records of the princely states, the pre-1947 provincial administration that came to the Indian side, revenue records, and a large collection of Persian and Urdu documents.
The equivalent records for the western districts are in Lahore, at the Punjab Archives in the Anarkali Tomb building, which holds among other things the records of the British Punjab administration.
Both are underfunded, understaffed and difficult to use. Access requires permission, cataloguing is partial, and conservation is a standing problem in a climate that destroys paper.
Digitisation has been piecemeal on both sides. The Panjab Digital Library has done more of it than either state.
The two archives together hold the documentary record of one province. Researchers on each side generally cannot visit the other, which means almost nobody has worked across the whole of it since 1947.
The Punjab State Archives holds Sikh period records, the Cis-Sutlej states' papers and the district records of the eastern districts. Much of it is in Persian and Urdu and cannot be used without those languages.
The Panjab Digital Library has scanned manuscripts, newspapers and books, largely on private and diaspora funding, and its holdings are the most usable body of Punjabi historical material online.
What neither archive holds is anything made by ordinary people. Letters, accounts, village registers and photographs are in houses, and nobody is collecting them.