Woodruff County is located in the Arkansas Delta in the U.S. state of Arkansas. The county is named for William E. Woodruff, founder of the state's first newspaper, the Arkansas Gazette. Created as Arkansas's 54th county in 1862, Woodruff County is home to one incorporated town and four incorporated cities, including Augusta, the county seat. The county is also the site of numerous unincorporated communities and ghost towns. Occupying only 587 square miles (152,000 ha), Woodruff County is the 13th smallest county in Arkansas. As of the 2020 Census, the county's population was 6,269. Based on population, the county is the second-smallest county of the 75 in Arkansas. Located in the Arkansas Delta, the county is largely flat with fertile soils. Historically covered in forest, bayous and swamps, the area was cleared for agriculture by early settlers. It is drained by the Cache River and the White River. Along the Cache River, the Cache River National Wildlife Refuge (NWR) runs north–south across the county, preserving bottomland forest, sloughs and wildlife habitat.

The Arkansas Delta is one of the six natural regions of the state of Arkansas. Willard B. Gatewood Jr., author of The Arkansas Delta: Land of Paradox, says that rich cotton lands of the Arkansas Delta make that area "The Deepest of the Deep South."