It has an area of 1,199 km², and a total population of 812,477 (2001). There are 141 communes in the province. As of may 31, 2005, the main communes by population are:
| Commune | Population |
|---|---|
| Varese | 96,917 |
| Busto Arsizio | 79,652 |
| Gallarate | 49,149 |
| Saronno | 37,502 |
| Cassano Magnago | 20,751 |
| Somma Lombardo | 16,571 |
| Tradate | 16,351 |
| Malnate | 16,020 |
| Samarate | 15,942 |
| Castellanza | 14,635 |
| Luino | 14,169 |
| Caronno Pertusella | 13,102 |
| Cardano al Campo | 12,949 |
| Lonate Pozzolo | 11,780 |
| Olgiate Olona | 11,517 |
| Fagnano Olona | 10,837 |
| Sesto Calende | 10,285 |