So I'm the family history buff and enjoy all things regarding both world wars. A few years back I was given a large collection of letters home written by a relative that served with the US Expeditionary force during the First World War. The letters span from 1916-1919. As much as I absolutely love reading through them; I admit that I am lacking the best methods to properly and effectively preserve them. I was wondering where might I begin to inquire about donating these letters and if indeed they are something deemed worth accepting by a museum or university. Thanks!
Letters (and all other records) belong in an archives generally, not a museum. I would recommend you explore donating these to a local history archives or historical society close to where your family is from, or if you or your family has ties to a particular university they might be interested in them. If you PM me some particulars about where you guys are from I can help you find some archives to "shop around" at. The Society of American Archivists has a nice little page for laypeople about what donating your family records is like.