is a tiny country located on the northeast coast of the Italian peninsula. It's population is about 30,000 and is surrounded on all sides by Italy.
Captain Regent Claudio hired ISIS for a security evaluation in which ISIS agents Sterling Archer and Lana Kane were to attempt to steal the San Marino Diamond, a large jewel kept in the San Marino Palace. Claudio chose ODIN over ISIS, due in large part to the poisoning of five palace guards while ISIS attempted to steal the diamond.
Agents Sterling Archer and Lana Kane returned to San Marino while the palace was under ODIN security in an attempt to steal the Diamond narrowly escaping under heavy fire. "The Rock"
San Marino on Wikipedia