| Statistic | Thetford Mines | Quebec | National |
| Population | 25,383 | 8,565,732 | 38,134,230 |
| Population density (sq km) | 113 | 6 | 4 |
| Median age | 52.5 | 42.6 | 40.9 |
| Male/Female ratio | 1.1:1 | 1.0:1 | 1.0:1 |
| Married couples | 52% | 50% | 66% |
| Families w/ kids at home | 31% | 40% | 43% |
| Speak English only | 0.1% | 4.7% | 68.8% |
| Speak French only | 77.7% | 49.5% | 4.5% |
| Data | Percent |
| Black | 0.5% |
| Latin American | 0.3% |
| Arab | 0.2% |
| Southeast Asian | 0.1% |
| South Asian | 0.1% |
| Data | Percent |
| United States | 0.4% |
| Colombia | 0.2% |
| France | 0.2% |
| Morocco | 0.1% |
| Mexico | 0.1% |