[1] The league was founded in mid-2011 by Courtney MacArthur, known as "Bev O'Lution" (and also as "Super Cali 'Agilistic' Expialidocious"),[2] a former skater with the Rocky Mountain Rollergirls who had moved to nearby Boulder, Colorado.

[3] The first practice attracted 35 potential skaters,[2] and by 2013 the league had around 100 members, and was also launching a junior roller derby program.

The Screaming Mimis and home teams are coached by Sydney Cooper Mortensen and Kaylee Hart, also known as Catastrophoebe and Bash Tag, respectively.

[7] Boulder County first qualified for WFTDA Playoffs in 2014, as the sixth seed at the Division 2 tournament in Kitchener-Waterloo, Ontario.

[13] Boulder County opened with a 162–82 win over ninth-seeded Chicago Outfit Roller Derby,[14] but then lost in the quarterfinals to Jet City Rollergirls 175–160.