Mavericks has revamped Apples support for external displays, making everything a lot easier when using a second or third monitor.
In previous versions of OS X, the dock was only accessible on your main display, however, and it seems the same way in Mavericks.
Until you realize, though, that there is a new, simple way to get the Dock on an external monitor.
The best part of this feature is that it’s built right in; there’s no need to mess with preferences or configuration files. First, make sure your Mac is connected to a second monitor (or third, depending on your Mac’s support for other monitor devices).
Then, move your cursor over to the bottom of the monitor you want to bring the Dock up on and put it wherever the Dock usually resides, either on the bottom, left, or right of your screen. When you do that, the Dock will pop over to the monitor you’re on, and slide into place.
Via: Mac Life