1794Military
== History ==
The city contains the site of Fort Defiance, built by General "Mad" Anthony Wayne in August 1794 during the Northwest Indian War.
1812Military
Fort Winchester was built on the same spot during the War of 1812, but it was a larger fort that extended southward somewhat along the Auglaize River.
1822History
In 1822, Defiance was laid out as a town.
1845History
In 1845, it was made the county seat of the newly created county, and it became a city in 1881.
1980History
In 1980, the park was added to the National Register of Historic Places.
2000History
=== 2000 census ===
As of the census of 2000, there were 16,465 people, 6,572 households, and 4,422 families living in the city.
2010History
=== 2010 census ===
As of the census of 2010, there were 16,494 people, 6,663 households, and 4,291 families living in the city.
2018History
The median value of owner-occupied housing units (2018–2022) was $135,800.
2022History
Census Bureau American Community Survey (ACS) median income for households (in 2022 dollars) was $58,750.