Zanesville, Muskingum County's county seat, was a well-established town by 1800, when statehood for Ohio was first discussed. But in 1800, there was no Muskingum County. Ohio might have 88 counties today, but in 1800, there were only seven, and Muskingum wasn't one of them. So if you are related to some of Muskingum County's earliest settlers, their land purchases and probate records aren't going to be found in Zanesville. Instead, those records will be at Marietta, the county seat of Washington County from which Muskingum was created in 1804. In 1800, Zanesville was just a town in Washington County.
No matter what state your ancestors settled in, you'll find there have been lots of shifting around of county lines. Finding the official records requires the researcher know when and how counties were formed, and there are several resources that will be very helpful.
But first, let's just look at the creation and evolution of Muskingum County.
The first map shows the Ohio Country counties as of 1800. Washington County is in green. The middle map shows the newly formed State of Ohio in 1804, one year after Statehood was granted, and the year that Muskingum County was formed mostly from Washington County and a small part of Fairfield County. Muskingum was a lot larger then than now, as you can see from the green area on the third map, which shows Ohio in 1818.
If you have ancestors in Tuscarawas, Coschocton, Guernsey, Morgan or Perry counties, you need to know that parts of those counties were once part of Muskingum. To locate those important genealogical records, ya gotta know the territory--how it changed, and where in those counties the ancestors lived.
Roseville is a good example of this. Some of my paternal ancestors lived Roseville. At one time they lived well within the boundaries of Muskingum County. Then along came Perry County, and Roseville found itself pretty much right on the county line. If I can't find certain records at the Muskingum County courthouse, I go to the Perry County Courthouse. But if I hadn't known about the change in the county line, I might have completely missed finding an important record.
Here are some resources useful in finding how and when county lines changed:
- The dates of formation of each of Ohio's 88 counties can be found at FamilySearch https://www.familysearch.org/wiki/en/Ohio_County_Creation_Dates_and_Parent_Counties
- The Newberry Library Atlas of Historical county boundaries features wonderful interactive maps. You choose from a range of dates and the map shows you the counties that existed at that time. Click on a county to identify it, and to see the date of formation as well as a description of the border changes. The Newberry Library Atlas can be used for any state, but I've included the link to Ohio here http://publications.newberry.org/ahcbp/map/map.html#OH
- Historical U.S. County Boundary Maps lets you type in a place name and a date, and shows you the county the place was in at that time in history https://www.randymajors.com/p/maps.html
- Finally, Thorndale and Dollarhide's book, Map Guide to the U.S. Federal Censuses, 1790-1820, remains an excellent resource for family historians. The book looks at the state of each state during each year a census was conducted there. The present-day counties are shown on each map, with the earlier county boundaries super-imposed on them, as shown in the example of Ohio in 1800 below. Most libraries, especially genealogy libraries, have a copy of this book.