The outer core of the Earth is approximately 2,200 kilometers (1,367 miles) thick.

However, it's important to note that "depth" isn't quite the right term. Here's why:

* Depth usually refers to the distance from the surface down.

* Thickness refers to the distance from the top of a layer to its bottom.

So, the outer core lies between 2,890 kilometers (1,796 miles) and 5,150 kilometers (3,200 miles) below the Earth's surface.