General:
* Pen
* Enclosure
* Roundup
* Gather
* Confine
* Round up
* Gather together
Figurative:
* Control
* Manage
* Organize
* Direct
More specific, depending on the context:
* Barn (for animals)
* Fold (for sheep)
* Stockyard (for cattle)
* Herd (for animals)
* Gather (for people)
* Round up (for people)
The best synonym for "corral" will depend on the specific context in which you are using the word.