The Castle Hill RSL sub-Branch provides comprehensive support and care for serving and ex-service Defence Force members and their dependents. It promotes government and community awareness of the need for a stable and progressive Australia while providing welfare and advocacy services. Additionally, it assists veterans in need, supports commemorating those who have served our country, and participates in employment programs. The branch provides moral and active support to the ADF and promotes loyalty and pride for the nation, the Crown, and the flag, while supporting the education of the youth of Australia about the achievements of veterans.