21 District

However, they were formerly known as G40 or 3T back in the early 2000s, and 2010s. They only changed their name to 21 District recently (2016-2019). They have links with another sub-gang called KVT.

G40
G40 was a very active youth-gang coalition in the early 2010's. They had big rivals such as [https://sydney-youth-gangs.fandom.com/wiki/Mount_Druitt "Mounty County" in Mount Druitt. ] There is not much to know besides that they were a big coalition of youth-gangs which was very violent, and fearless as seen in the Westfield Attack in Mount Druitt.

Most of G40's members are adults/young-adults now, they paved the way for the newer generation of youth-gangs.

21 District
21 District, also known as the "Innerwest Brotherhood", is currently a gang coalition comprising of mostly all of the suburbs with postcodes starting with 21, such as Guildford (2161), Merrylands (2160), Blacktown (2148), Smithfield (2164), and many more.

21 District is also a "music group", and just like ONEFOUR, they claim to be for "entertainment purposes" (obviously only because they do not want to be sued, or have trouble with the police), but are still very much active and part of the youth-gang scene.

Rivals
Their rivals are not speculation, and known social media accounts affiliated with them have made it clear.

Unlike Mounty County, 21 District's coalition is still somewhat steady, and their main rivals are all youth-gangs located in or near Mount Druitt (2770). It is almost impossible to determine what groups are rivals and which is not, as there are many youth-gangs inside 21 District that have different opinions and feelings, but the majority only rival with the Greater West gangs such as ONEFOUR and Section 60. This rivalry has been ongoing for decades, and the reason for this beef is mixed.

Allies
21 District has a good relationship with many groups within Doonside (2767), notably Hooligan Hef's group.