20.7% of the population for whom poverty status is determined in Mountainburg, AR (117 out of 566 people) live below the poverty line, a number that is higher than the national average of 12.5%. The largest demographic living in poverty are Males 55 - 64, followed by Females 55 - 64 and then Males 65 - 74.

The most common racial or ethnic group living below the poverty line in Mountainburg, AR is White, followed by Native American and Black.

The Census Bureau uses a set of money income thresholds that vary by family size and composition to determine who classifies as impoverished. If a family's total income is less than the family's threshold than that family and every individual in it is considered to be living in poverty.