In the USA roller derby is really popular, it was brought back in flat track in 2001 by Texas's so in Texas's its pretty popular or Canada but mainly the US unlees your talking about junior roller derby, if so then Canada
Greensboro Roller Derby was created in 2010.
Roller Derby - brand - was created in 1936.
Roller Derby Germany was created in 2011.
Helsinki Roller Derby was created in 2009.
Houston Roller Derby was created in 2005.
Pacific Roller Derby was created in 2008.
Junior roller derby was created in 2007.
Roller Derby Toulouse was created in 2010.
Wasatch Roller Derby was created in 2008.
NEO Roller Derby was created in 2007.
Toronto Roller Derby was created in 2006.