Pannonia Prima included parts of present-day Hungary, Austria, Croatia, Slovenia, and Slovakia.

It was bordered on the west by the Alps, which stretch from the Danube River to the Adriatic Sea, and belonged to the provinces of Noricum.

The foederati and Visigothic and Hunnic barbarians caused trouble, and the situation in Pannonia was described by Claudian as "a continual siege" in 399.

Pannonia Prima held out under Generidus, but was eventually assimilated into the Huns' territory by 427.

Rome would never regain effective control of this area, but nominally remained a Roman province, until the fall of the Ostrogothic Kingdom in 553.