High Quality Content by WIKIPEDIA articles! Olive Branch is a city in DeSoto County, Mississippi, United States. The population was 21,054 at the 2000 census. A July 1, 2008 United States Census Bureau estimate placed the population at 31,830, making it the ninth-largest city in the state of Mississippi. Olive Branch is a suburb of Memphis, Tennessee and is part of the Memphis Metropolitan Statistical Area, a region that consists of three counties in southwest Tennessee, four counties in northwest Mississippi, and one county in eastern Arkansas.