Unirea, Alba Demographics Historical population

| Year_ | Total | Romanians | Hungarians | Roma_ |
|---|---|---|---|---|
| 1850 | 4541 | 69.3% | 23.9% | 6.5% |
| 1880 | 4636 | 63.0% | 30.2% | n/a |
| 1890 | 5499 | 62.7% | 31.6% | n/a |
| 1900 | 5553 | 64.3% | 29.7% | n/a |
| 1910 | 6234 | 64.6% | 30.4% | n/a |
| 1920 | 5887 | 71.6% | 27.9% | n/a |
| 1930 | 6456 | 70.5% | 22.8% | 2.6% |
| 1941 | 6981 | 78.3% | 19.4% | n/a |
| 1956 | 6649 | 74.7% | 19.0% | 6.0% |
| 1966 | 6991 | 80.9% | 17.3% | 1.7% |
| 1977 | 7089 | 78.1% | 16.9% | 4.9% |
| 1992 | 5723 | 74.1% | 14.2% | 11.6% |
| 2002 | 5506 | 74.4% | 12.0% | 13.6% |
| 2011 | 4574 | 70.7% | 11.2% | 17.9% |