Over the past 19 years, I have gone through thousands of issues of Civil War era newspapers from throughout the state of Ohio and along the way have indexed quite a few of them. The focus of the indexes is to have a list of all the soldiers letters that saw print within- sometimes it takes a bit of digging to determine who the correspondents are but for the most part. Thus far, I have documented over 6,800 letters from more than 40 newspapers titles from around the state. As more than 210 different titles were printed during the war, about 20% of the issues have been indexed.
And don't think that the only thing you'll find within are letters from Ohioans- soldiers from all around the country wrote home to Ohio and it was not uncommon to see letters from states as diverse as Iowa or Pennsylvania, along with letters from sailors in the blue and brown water navies. I am continually amazed at the quality of the accounts published during the war years, and think that any serious work studying the campaigns of the war should have a solid basis in these accounts.
You'll find that some of these are uploaded as Excel files and some as PDFs. The Excel files are newer and laid out such that I can use the data for a far larger Master file (not shared here). My apologies for any errors- enjoy!