Dayton is located at 39°45'30" North, 84°11'29" West (39.758611, -84.191389).
According to the United States Census Bureau, the city has a total area of 56.63 mi2 (146.66 km2). 55.78 mi2 (144.46 km2) of it is land and 0.85 mi2 (2.20 km2) of it is covered by water. The total area is 1.50% water.
Dayton is located in the Eastern Standard Time (EST) timezone, GMT-05:00. It observes Daylight Saving Time (DST).