Check out these sites to get more info.

http://www.milestonemx.com/

http://www.perrisraceway.com/

http://www.glenhelen.com/

http://www.baronaoaks.com/

http://www.avmotoplex.com/location.htm

http://www.calcitymxpark.com/

http://www.racetown395.com/

http://www.ridecemx.com/

http://www.lakeelsinoremxpark.net/

http://www.pirumx.com/

http://www.adelantomx.com/

http://www.lacrmx.com/

http://www.i5mx.com/

http://www.starwestmx.com/

http://www.ccmxpark.com/

http://www.ridgecrestmx.com/