Start by asking the police to evict them.
https://www.landlordology.com/how-to-get-rid-of-squatters/
File for an injuctive order declaring that the person is not a tenant, and they have to leave. A Housing Court might be a good idea, if available. Added: Agree with above answer - also- it may depend on how long the 'squatter' has been occupying the premises. He might have become a 'tenant' by 'right of adverse possession.' You will have to do some checking into the local statutes that govern landlord/tenant relations in your julrisdiction.
Depends on the state.
Illinois is a state.
One can evict a renter or a squatter, but not an owner of the property. However, you should consult with an attorney in your area who can review your situation and explain your rights and options. You do not have to allow a stranger, the girlfriend, to live in your home.
The white-tailed deer is official state animal of Illinois. The northern cardinal is official state bird of Illinois. The monarch butterfly is official state butterfly of Illinois. "State sovereignty, national union" is the official state motto of Illinois. Land of Lincoln is official state nickname of Illinois. Pumpkin pie is the official state pie of Illinois. "Illinois" is the title of the official state song of Illinois. The white oak is official state tree of Illinois.
"Illinois" is the title of the official state song of Illinois.
Goldrush apple is the official state fruit of Illinois.
State of Illinois
There is no Illinois state cat.
Illinois.
"Illinois" is the title of the official state song of Illinois.
None, there are no squatter rights anymore.