A micronation is a political entity whose representatives claim that they belong to an independent nation or sovereign state, but which lacks legal recognition by any sovereign state. Micronations are classified separately from de facto states and quasi-states; they are also not considered to be autonomous or self-governing as they lack the legal basis in international law for their existence. The activities of micronations are almost always trivial enough to be ignored rather than disputed by the established nations whose territory they claim—referred to in micronationalism as macronations. Several micronations have issued coins, flags, postage stamps, passports, medals and other state-related items, some as a source of revenue. Motivations for the creation of micronations include theoretical experimentation, political protest, artistic expression, personal entertainment and the conduct of criminal activity. The study of micronationalism is known as micropatriology or micropatrology.

Micronations are ephemeral, self-proclaimed entities that claim to be independent sovereign states, but which are not acknowledged as such by any recognised sovereign state, or by any supranational organisation. The constant reiteration of the flag as a symbol of a something that exists by the entity that it symbolizes confirms the validity of the flag as an officially sanctioned and/or definitive symbol of an entity; therefore, there has been a close association between vexillology/vexillogic imagination in creating visual symbols that appear to legitimize micronational claims.