Fanshawe is located at 34°57'2" North, 94°54'29" West (34.950556, -94.908056).
According to the United States Census Bureau, the town has a total area of 22.72 mi2 (58.84 km2). 22.59 mi2 (58.51 km2) of it is land and 0.13 mi2 (0.33 km2) of it is covered by water. The total area is 0.56% water.
Fanshawe is located in the Central Standard Time (CST) timezone, GMT-06:00. It observes Daylight Saving Time (DST).