From a former section on the Wikipedia page on expatriates 
The Expatriate Archive Centre in The Hague (Netherlands) has a unique collection of letters, diaries, photographs and films documenting the social history of expatriate life. It collects journals, letters, diaries and photographs – in fact, almost any document from the past detailing the lives and experiences of people working and living away from their home country.
The Expatriate Archive’s purpose is to collect, preserve, promote, and make available to the public and researchers a collection of primary source materials documenting the social history of expatriate life. It aims to give a voice to the memories and experiences of expatriates of all nationalities from all over the world, and to establish a research resource for historians worldwide
The website is .