Starting a regional is a LOT of work.
First you will need support of the regional director in the area, as others have said. Then you need a facility that can host 40-60 teams for the pit area, have sufficient field area, extra rooms for judges, volunteers and other staff, sufficient power to provide power to the pits and fields, availability usually from Wed-Sat night. You need to put together a planning committee to help bring in all the volunteers (about 140) needed to run the event, provide food to feed volunteers, guest speakers, maybe a team social, insurance, lighting and sound equipment, etc..
Oh yeah, you also get to raise ALL the money needed to pay for all this.
And regionals are sanctioned based on FIRST's needs, so you need a thumbs up from headquarters before you even get started.
There is a document on the FIRST web site that describes this...
http://www.usfirst.org/roboticsprogr...ning-committee