Dinajpur Rajbari is located at the North-East part of the town. The name of the location is "Raj Batika", just near to the Rajarampur village. You don't need to remember the names, just ask any people about the "Rajbari" and they will guide you.
Actually the Rajbari is all in its ruins. Most of the edifices are destroyed now a days. Only few structures are left. While entering the rajbari, you have to cross two large facades, one is currently white colored, and another is called "Lion Gate".
Inside the Rajbari premises, you'll find two Mondir, a praying place for the Hindu religions. Among those, one is active. You'll find several statue of the Hindu gods and goddesses inside the Mandir.
This place is not acquired by Bangladesh Government. Thats why there is no care is taken. Inside the ruins of the old rajbari, people used to leave the wastes from their bowls, or sometimes urination.
I have added few photos of the Rajbari here.