Harvard University Library has digitised and made openly available archives relating to the Harvard Expedition to Samaria, led by American archaeologist George Andrew Reisner, between 1908 and 1910. The archives include Reisner's diaries from the period, and diaries from a few of his colleagues, including Gottlieb Schumacher, 
David Gordon Lyon, and Clarence Stanley Fisher.

Scope: diaries, photographs, expedition admin documents
Reisner diaries 1909-10
Fisher journal 1908
Lyon diary 1908-11
Schumacher diary 1908
Schumacher Report 1908
Expedition summary 1909
Harvard expedition to Samaria notebook 1910
Antiquities Register
Accounts Book
Photographs list
Expedition correspondence 1901-9
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Further Reading 
AWOL, 2014. Harvard Expedition to Samaria 1908-10. Ancient World Online.

This archive was housed in a sealed room in the site of Abydos, in Egypt, and discovered in 2013. Records relate to the Egyptian Antiquities Service between the 1840s and the 1960s, a critical period for archaeology in Egypt.  Importantly, this archive reflects to the work of Egyptian inspectors and guards in the Egyptian Antiquities Service during this period. The project is currently conserving  and cataloguing the archive, and preparing a searchable database of the collection.

Twitter: @AbydosArchive
Blog: abydosarchive.org/

Further Reading: 
Shalaby, N., Abu El-Azm, H., Damarany, A., Kaiser, J., Abdallah, H.S., Abu El-Yazid, M., Abd El-Raziq, Y., Baker, F., Hashesh, Z., Ibrahim, W., Minor, E., Regelein, R. and Tarek, A. 2018. The Lost Papers: Rewriting the Narrative of Early Egyptology with the Abydos Temple Paper Archive. ARCE Bulletin [Online]: https://www.arce.org/abydos-paper-archive
Abydos Temple Paper Archive Project. Egypt Exploration Society website: www.ees.ac.uk/atpa