My father passed in 2004. I am his only son and the bearer of our Family name. At my father's repass I gave the keys to my father's house to my aunt and informed her I would return in 2 -3 months. My aunt moved into the property and all my attempts to contact her have been ignored. I researched the property information and the deed is in my name (My father did not have a will). What actions are possible to gain possession of the property?

You send her a vacate notice giving her 30 days to move out. If she doesn't, then you file for an eviction order.

Yes , does DC stand for District of Columbia in the US, since you use some strange terms for the US and ones that do not matter. " Only son and bearer of the family name" this means nothing, what means something is how the property got deeded over to you after your fathers death, you were either a joint owner with rights to property at death, or it went though probate and was deeded over to you.

The deed does not automatically just change to you.

"Gave keys to fathers house " OK I assume it means you agree to rent to her ( perhaps at no charge) What was the agreement ?