| Parish | 1901 | 1911 | 1921 | 1931 | 1951 | 1961 | 1971 | 1981 | 1991 | 2001 | 2011 | 2022 | % change 1901 to 2022 |
| Barra | 2,545 | 2,620 | 2,456 | 2,250 | 1,884 | 1,467 | 1,090 | 1,339 | 1,282 | 1,172 | 1,264 | 1,301 | -48.9 |
| Barvas | 6,736 | 6,953 | 6,660 | 5,876 | 5,111 | 4,331 | 3,983 | 3,994 | 3,550 | 3,133 | 3,244 | 2,975 | -55.8 |
| Harris | 5,271 | 5,449 | 5,276 | 4,468 | 3,991 | 3,284 | 2,885 | 2,780 | 2,418 | 2,120 | 2,054 | 1,967 | -62.7 |
| Lochs | 4,733 | 4,750 | 4,396 | 3,849 | 3,111 | 2,456 | 2,167 | 2,319 | 1,957 | 1,814 | 1,810 | 1,837 | -61.2 |
| North Uist | 3,891 | 3,677 | 3,223 | 2,827 | 2,221 | 1,925 | 1,722 | 1,727 | 1,649 | 1,521 | 1,481 | 1,438 | -63.0 |
| South Uist | 5,516 | 5,383 | 4,844 | 4,236 | 3,764 | 3,997 | 3,871 | 4,451 | 4,120 | 3,200 | 3,227 | 3,093 | -43.9 |
| Stornoway | 12,983 | 13,438 | 13,366 | 12,116 | 12,791 | 12,717 | 12,232 | 13,409 | 12,733 | 12,015 | 13,009 | 12,060 | -7.1 |
| Uig | 4,497 | 4,462 | 3,956 | 3,364 | 2,718 | 2,430 | 1,947 | 1,824 | 1,661 | 1,527 | 1,595 | 1,469 | -67.3 |
Figures in bold italics indicate years, which showed a population increase