The precursor to the Diözesanarchiv Eichstätt (Eichstätt Diocesan Archive), the archive of the ecclesiastical council of the principality of Eichstätt, had been trying to transfer the ecclesiastical council and vicariate's minutes and files from the ecclesiastical principality's archives to its own archive since 1785. It was only when secularisation threatened that these files were then merged with the ecclesiastical council's registry in 1801/02. During the course of secularisation, the ecclesiastical principality's archives and the archives of the cathedral chapter were transferred to the Bavarian state in 1806 and the ecclesiastical council's files, which had been separated out in 1801/02, had to be handed over to the Imperial Archive in Munich for the most part in 1812. In 1861 Joseph Georg Suttner was appointed archivist of the episcopal ordinariate and established a new system.
The archive was officially established in 1970 with a full-time archivist under the name "Diözesanarchiv" (Diocesan Archive). During the course of its foundation, its holdings were moved completely from the cathedral provostry's banqueting hall to the ground floor. However, as the capacity was not sufficient, construction work began on the Domherrenhof Ostein in 1988, which was completed in 1993/1994.
The archives date back to the 12th century. In addition to administrative files and documents, the archive also houses association archives, special collections and estates.
The holdings are divided into the following main groups: