 defiance county is a county located in the u.s. state of ohio. according to the 2010 census, it has a population of 39,037, which is a decrease of 1.2% from 39,500 in 2000. its county seat is defiance. the county was named after an early army fortification, fort defiance, which was so named by mad anthony wayne to signify the settlers' "defiance" of the indians. the defiance, oh micropolitan statistical area includes all of defiance county. ==geography== according to the 2010 census, the county has a total area of , of which  (or 99.34%) is land and  (or 0.66%) is water. ===adjacent counties=== *williams county (north) *henry county (east) *putnam county (southeast) *paulding county (south) *allen county, indiana (southwest) *dekalb county, indiana (west) ==demographics== {{uscensuspop |1850=6966 |1860=11886 |1870=15719 |1880=22515 |1890=25769 |1900=26387 |1910=24498 |1920=24549 |1930=22714 |1940=24367 |1950=25925 |1960=31508 |1970
1845_establishments_in_the_United_States Defiance_County,_Ohio Ohio_counties