12.1% of the population for whom poverty status is determined in Firth, ID (52 out of 429 people) live below the poverty line, a number that is lower than the national average of 12.5%. The largest demographic living in poverty are Females 25 - 34, followed by Males 55 - 64 and then Males 75+.

The most common racial or ethnic group living below the poverty line in Firth, ID is White, followed by Other and Hispanic.

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.