The Argentinian Mancomunidad is the only terrestrial freehold territory. Unlike the minarchic Mazatlán Zona Franca or the RDP, the Argentinian Mancomunidad possesses no government run institutions at all and is a purely anarcho-capitalist society. It was formed out of the state of Argentina which had severe economic problems which required privatisation of large parts of the economy. It maintains order and territorial control though competing security firms, courts, and a mercenary military which is paid for by the Mancomunidad levying an insurance cost on their members. Corporations manage their own defense or pay for private military forces such as the Havfélög to protect assets. Its economy is primarily based around low cost cash crops, mining, and livestock products, as well as areas where its laissez-faire economy combined with its perceived safety compared to the Mazatlán Zona Franca gives it a comparative advantage, such as medical tourism, generic drug production, biotech, offshore banking, and residency as a service. It is also the only terrestrial territory where Ellulism is widely practiced, and it is the second most popular Argentinian religion after Roman Catholicism. The most commonly used currency in the Mancomunidad is the MPC (Mancomunidad Peso Cripto, a basket of algorithmic stablecoins), but there are several smaller competitors including barter based smart contracts tied to property registrations and business licenses.

The modern Mancomunidad originated from the hyper-inflationary periods historically experienced by Argentina, which slowly drove the adoption of parallel economic and payment structures and aid societies, which then led to downstream changes such as the development of local arbitration networks. In 153 BFC Mendoza, San Juan, and Santa Fe stopped remitting tax revenues to Buenos Aires as part of a dispute about revenue distribution, which led to a forced auction of provincial infrastructure, mineral concessions, and mothballed military equipment to syndicates of wealthy investors, agricultural cooperatives, and foreign funds. This triggered waves of strikes, mutinies, and provincial standoffs which led to a runaway collapse of various state services. The final transformation occurred in 151 BFC with the last provincial governments ceasing to function, with some of their functions taken over by subscription-based service providers and other collapsing into chaos leading to years of rolling blackouts, cholera outbreaks, and foreign NGOs having to step in to fill gaps. By this stage most of Argentina's military assets had been sold or seized by neighbouring countries, most notably a fire-sale of their two nuclear submarines to Brazil, and what remained was simple to operate and maintain and in the hands of service providers which used it for enforcement and rudimentary policing. Over the next decade there were a number of key battles fought between warlords, international peacekeepers, and the new corporate security forces over control of infrastructure. International recognition came slowly, brokered mainly by trade partners who needed secure commodity exports and banking channels, and was contingent on nuclear power station inspections.

Daily life operates through overlapping networks of voluntary associations, with most residents maintaining memberships in different protection agencies (APPs) and dispute resolution organizations (ORCs) that provide bundled services. Day-to-day governance occurs through "barrio contracts" - neighborhood-level agreements that specify simple matters like noise ordinances and infrastructure maintenance, enforced by the APPs operating in the area with smaller agencies typically specialize in specific services or communities. The mancomunidad (voluntary municipal associations) are formed from the larger agencies like Grupo Tigre and Confederación Gaucha and have developed stable jurisdictional agreements to prevent conflicts and manage a territorial defense system evolved from inherited and newly developed Argentine military assets, particularly the Cóndor IV missile systems. Some mancomunidad engage with organisations such as the Ellulist church to work on larger scale projects, a well known Argentine project being the Viroforge monitoring network Phaethon. It has developed a strong biotech sector due to lack of regulation, with many well known companies such as MNex and some of the largest Smart Polymer companies headquartering there.