[3] Gilmore is located in northern Crittenden County and is bordered to the south by the city of Turrell.

According to the United States Census Bureau, Gilmore has a total area of 0.23 square miles (0.6 km2), all land.

[4] Ecologically, Gilmore is located within the Northern Backswamps ecoregion within the larger Mississippi Alluvial Plain.

The Northern Backswamps are a network of low-lying overflow areas and floodplains historically dominated by bald cypress, water tupelo, overcup oak, water hickory, and Nuttall oak forest subject to year-round or seasonal inundation.

[5] The Wapanocca National Wildlife Refuge, which preserves some of the year-round flooded bald cypress forest typical of this ecoregion prior to development for row agriculture lies southeast of Gilmore.