FIRP Home: "In the First Person is a free, high quality, professionally published, in-depth index of close to 4,000 collections of personal narratives in English from around the world."
An interesting (unfortunate?) twist to FIRP is that it indexes both free and subscription databases. A quick search for "Oregon Territory" brings us to 55 documents, every one of them part of the subscription only North American Women's Letters and Diaries database. Other searches for PNW topics also brought me to password walls more often than to freely accessible documents. Fortunately you can go to an advanced search screen and limit your search to free documents.
Digital history geeks will be impressed by the range of options on the advanced search page. You can search by the age of the person person writing or being interviewed, for example, or their year of birth, or for only unpublished sources. Setting up such a search is not great technical feat (I am told), the hard part is entering all the metadata.
There isn't a lot at this site yet for the Northwest historian, but it is worth keeping an eye on as its collection expands.
Next: Other Online Sources of First-Person Accounts