| Statistic | Thornhill | Markham | Ontario |
| Population | 6,698 | 359,111 | 14,804,681 |
| Population density (sq km) | 3,103 | 1,675 | 15 |
| Median age | 45.9 | 40.7 | 40.9 |
| Male/Female ratio | 1.1:1 | 1.0:1 | 1.0:1 |
| Married couples | 71% | 82% | 71% |
| Families w/ kids at home | 45% | 58% | 46% |
| Speak English only | 87.4% | 84.1% | 86.1% |
| Speak French only | 0.0% | 0.0% | 0.3% |
| Data | Percent |
| West Asian | 14.6% |
| Chinese | 12.6% |
| Korean | 7.5% |
| Filipino | 5.0% |
| Latin American | 3.5% |
| Data | Percent |
| Iran | 11.8% |
| China | 6.1% |
| Philippines | 5.9% |
| South Korea | 4.7% |
| Russia | 2.2% |