District 12 is the poorest District in Panem and it's specializes in mining coal.
District 12 Seal
Description
District 12 lies in the Appalachia region and with a population of around 8,000 people. It is the poorest District, even then District 13 which is obliviated. It is also one of the farthest Districts away from the Capitol, other than District 13. District 12 main industry is mining coal.
Links
District 12 (The Hunger Games Wiki)