The Principality of Purgaz[1] (Russian: Пургасова волость, romanized: Purgasova volost; Erzya: Пургазонь Русесь, romanized: Purgazoń Ruseś), also referred to as the Purgas Volost,[2] was a "Mordvin" principality located between the Oka and Sura rivers.

The principality is an important part of Mordvin history and is notable for marking the first time the Erzyas and Mokshas united under a single polity.

[3] Erzya prince Purgaz entered the war against Vladimir-Suzdal in 1229, forging an alliance with Volga Bulgaria.

Puresh's son Atämaz initially won several victories, and Purgaz barely escaped amidst widespread massacres of the Erzya population.

[1] Much information on the Principality of Purgaz remains unknown, including its capital and exact borders.