Mequon is located at 43°14'11" North, 87°59'3" West (43.236389, -87.984167).
According to the United States Census Bureau, the city has a total area of 46.82 mi2 (121.26 km2). 46.18 mi2 (119.61 km2) of it is land and 0.63 mi2 (1.64 km2) of it is covered by water. The total area is 1.36% water.
Mequon is located in the Central Standard Time (CST) timezone, GMT-06:00. It observes Daylight Saving Time (DST).