The oldest continental crust is estimated to be around 4.03 billion years old. This crust is found in the Slave Craton in northwestern Canada.

It's important to note that:

* The age of the oldest continental crust is constantly being revised as new discoveries are made.

* Not all continental crust is that old. Most continental crust is much younger, with an average age of about 2 billion years.

* The oldest continental crust is often found in cratons, which are the stable, ancient cores of continents.

Let me know if you'd like more details about the Slave Craton or the process of continental crust formation!