From Rome southward the Appian Way's course was almost straight until it reached Tarracina (Terracina) on the Tyrrhenian Sea. The road then turned inland to the southeast to reach Capua. From Capua it ran east to Beneventium (Benevento) and then southeastward again to reach the port of Tarentum (Taranto). It then ran east for a short distance to terminate at Brundisium.

The Appian Way was celebrated by Horace and Statius, who called it longarum regina viarum, or “queen of long-distance roads.” As the main highway to the seaports of southeastern Italy, and thus to Greece and the eastern Mediterranean, the Appian Way was so important that during the empire it was administered by a curator of praetorian rank. The road averaged 20 feet (6 m) in width and was slightly convex in surface in order to facilitate good drainage. The road's foundation was of heavy stone blocks cemented together with line mortar; over these were laid polygonal blocks of lava that were smoothly and expertly fitted together. The lava blocks formed a good traveling surface, and one that proved to have extraordinary durability over the centuries. The first few miles of the Appian Way outside Rome are flanked by a striking series of monuments, and there are also milestones and other inscriptions along the remains of the road.