Although not among the most dire consequences of the global caronavirus pandemic, the closure of libraries, universities, museums, and other organizations has made it challenging to do historical research these past two years. Fortunately, we live in an age when online historical research -- even with primary sources -- is not only possible, it's also largely free and often quite fruitful. Here are some basic resources I've been using to continue doing research into U.S. history online.
Free
This is a crowd-sourced platform with "memorials" added by individual users, although there is a method that allows for official designation of notable persons. The most reliable information here are the photos of headstones, although those can occasionally have an erroneous date of birth or even death! Still, it can be a good starting place to narrow down those dates for further research, and some memorials have added obituaries or other biographical information that can provide helpful clues. If you happen to like strolling through old graveyards, you can also volunteer to help those looking for photos of headstones by taking a picture and uploading it to the site.
As part of its mission to "organize the world's information," Google has uploaded innumerable published books that are in the public domain to its Google Books service and made most of them full-text searchable (with the usual drawbacks of OCR). You can add a book to your personal online bookshelf and any highlights you make in your online copy will also be saved to a separate document on your Google Drive (assuming you have one) making it a lot easier to organize quotes and citations than, say, Amazon's Kindle app.
You can also use the site to search books that are not in the public domain, but you'll have limited access to single pages. This is usually enough to help establish if a book may be useful before purchasing it through the provided links to multiple online retailers.
The Internet Archive is a repository for an incredible amount of public domain, copyleft, and other freely-available media. It's not limited to books and includes audio recordings, video games, and lots of other valuable content. Although there is some overlap with Google Books, I have often found documents on one site that aren't on the other.
The National Archives of the United States provides an online catalog to look for government records and the ability to contact researchers for assistance. It also hosts some digitized documents on its website, making it possible to work with primary sources right in your web browser.
The Library of the United States Congress is famous as a repository for published works of all kinds, as well as manuscripts useful for historical research. The LOC has perhaps even more digitized primary sources freely available on its website than the National Archives does, including the personal correspondence of early Presidents.
This is just one example of the many historical societies across the United States that are the stewards of unique documents that cannot be found anywhere else, including manuscripts, artworks, artifacts, ephemera, and much more. The Maryland Center for History and Culture has made portions of its collection available online through photographs and scans. These kinds of historical societies exist at the local level as well.
This is an example of a branch of the United States Armed Services that has documented and curated its own history and made much of it available online. In the case of the NHHC, this includes transcriptions of documents in addition to photographed and scanned materials. Other Armed Services provide historical information freely online as well.
Paid
On the plus side, there's nothing like reading through old newspapers to get a sense of contemporary events and unearth bits of biographical information. There's an impressive number of newspapers available here going back to at least the early 1800s. Although there may be a free option, paid subscriptions are not what many people would consider "cheap" and the list of available newspapers is far from comprehensive. Following up on a useful citation only to find that Newspapers.com doesn't have that paper can be frustrating, but overall it certainly beats a trip to a distant library to stare into a microfilm machine all day. Newspapers.com is also available as a package subscription with Ancestry.com, which I'll cover in another post.