<page_title> Mercer County, Ohio </page_title> <section_title> Demographics </section_title> <table> <cell> 2010 <col_header> Historical population </col_header> <col_header> Census </col_header> </cell> <cell> 40,814 <col_header> Historical population </col_header> <col_header> Pop. </col_header> </cell> </table>
As of the census of 2010, there were 40,814 people residing in the Mercer County.