| Statistic | Sainte-Marthe-sur-le-Lac | Quebec | National |
| Population | 20,759 | 8,565,732 | 38,134,230 |
| Population density (sq km) | 2,210 | 6 | 4 |
| Median age | 37.9 | 42.6 | 40.9 |
| Male/Female ratio | 1.0:1 | 1.0:1 | 1.0:1 |
| Married couples | 46% | 50% | 66% |
| Families w/ kids at home | 49% | 40% | 43% |
| Speak English only | 1.2% | 4.7% | 68.8% |
| Speak French only | 49.2% | 49.5% | 4.5% |
| Data | Percent |
| Black | 3.2% |
| Arab | 2.1% |
| Latin American | 1.1% |
| Southeast Asian | 0.6% |
| Chinese | 0.4% |
| Data | Percent |
| France | 0.9% |
| Morocco | 0.7% |
| Other Western Africa | 0.6% |
| Algeria | 0.5% |
| Romania | 0.5% |