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Mercer County Ohio Genealogical Society

PO Box 437

Celina, Ohio 45822


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Mercer County History

Mercer County was founded in 1820 which set it apart from Darke County. Land south of the Greenville Treaty Line was still part of Darke County. An act establishing Mercer County took place on January 2, 1824. In 1837 Van Wert County was detached and the county line established is the current northern border of Mercer County. In 1839 Celina was established as the capital of Mercer County, St. Marys, Ohio was the previous capital. In 1848 the area south of the Greenville Treaty Line to the current southern county line, was attached. When Auglaize County, Ohio was formed, Mercer County’s eastern border was moved 6 miles west with the exception of the area south of the Greenville Treaty line. This created the sharp point at Mercer County’s south-east corner and was the last county line modification. In the mid to late 1800s Mercer county became home to many German immigrants, most of whom became farmers in the new world. Many of these German immigrants migrated from northwestern Germany.

Meeting Information

Richardson-Bretz Building
(Behind the Celina Library)

119 W Fulton St, Celina OH 45822

 The Mercer County Chapter of the Ohio Genealogical Society meets the first Sunday of each month at 2:00pm.  
As always, the meetings are open to the public. We would love to have you join us.

Meeting Location

Richardson Bretz Building


Join Us Today!

Find our membership form here.




Publications Order Form

First & Pioneer Families

First Families: before 31 December 1860
Pioneer Families: from 1 January 1861 to December 1880

You must be a member of the Mercer County Chapter of Ohio Genealogical Society. An
application must be completed and submitted along with an application fee of $ 15.00 by the
end of August in the given year.

Find information about the requirements and appplication here.