All of the Texas Longhorn cattle in Australia are registered with one or more breed registries located in the USA and also Australia. The first breed registry formed was the Texas Longorn Breeders Association of America in 1964. The TLBAA webiste is an interesting source of information with a page devoted to what TLBAA is about.
A new organisation, the international Texas Longhorn Association was formed in 1990 and you can read more about the history and formation of the ITLA on their website.
The Australian breed registry Texas Longhorn Australia was incorporated in 2010 by a group of Texas Longhorn enthusiasts and breeders in NSW. Unlike the breed registries in the USA, it allowed the registration of cross bred Texas Longhorns with an integrated breeding up process with its Breeding & Registration plan and now enjoys wide support and has registered in excess of a thousand Texas Longhorns in this country. TLA conducts an annual sale in September each year at Scone, NSW.
There are also other organisations in the USA and Canada, namely: Cattleman's Texas Longhorn Registry, Texas Longhorn Marketing Alliance, Canadian Texas Longhorn Association. There are breeders of Texas Longhorns in Europe as well which can be found with a Google search of the internet.
Below are contact details and links to the organisations that register the vast majority of the Texas Longhorns in Australia.