Do you look for online county histories when you do genealogy research online? I don’t think looking for a county history would be the first plan of attack when hunting down ancestral information.
With their publishing heyday ranging from c1875 to the early 1900s, most of these county histories, or mug books are they are sometimes called, are now copyright free and in the public domain. Many have been digitized and can be accessed online.
If you are researching U.S. families in the post-Civil War era into the beginning of the 20th century, county histories should definitely be a resource on your “to do” list.
Why??? Because:
1. Your ancestor and/or his collateral family might have an article in the book.
2. Entries often contain details perhaps not found elsewhere.
3. If you are really lucky, there might be a photograph.
4. If if your ancestor has no family article included, it’s important to know the history of the places where your family lived. County histories supply incredible details about settlement of towns, local economy, church and school history and much more. Your family might be mentioned in this portion of the book.
As with any genealogical resource, there are some warnings to be given. Families paid a fee to have their entries published in these books. No editor double checked any information contained in them and families could submit whatever they wanted.
First, there might be errors because of failed memories or mis-information, especially if the article talks about long deceased parents, grandparents and immigrant ancestors.
Second, the family history/stories might have been “embellished” to make them appear more important.
Third, the family might have outright lied about portions of their stories. I’ve come across an entry touting the patriotic Revolutionary War service of an ancestor. Well, yes, the ancestor did have war service, but he was a noted Tory and run out of town!
Treat each article as you would an online family tree – the “facts” are clues to be followed and verified or disproven.
Having said that, many biographical articles are true gems that fill in previously unknown details about an ancestral family.
Here is an entry for Joseph Addison Brasher, the brother of my husband’s 2X great grandfather, Emsley Harrison Brasher in a state mug book, The Biographical Souvenir of the State of Texas, 1889.

It confirms that he and Emsley were the only two surviving children of Hampton Brasher. It gives the birthplace of Hampton, adds in that he had failing health at one point in his life and died in the Confederate Army in 1864. The article also obviously tells much about the life of Joseph himself.
Where Can County Histories Be Found Online?
More and more digitized copies of these county histories can be found online and are free to access. Here are several websites:
Online County Histories, Biographies & Indexes – USA, by Joe Beine
FamilySearch Books – Enter the county and state name.
WorldCat is another option. If the county history you are seeking hasn’t been digitized yet, WorldCat will also tell you the location of the closest library to you that has your book in its collection.