Pontine marshes
The Pontine Marshes, termed in Latin Pomptinus Ager by Titus Livius,Pomptina Palus (singular) and Pomptinae Paludes (plural) by Pliny the Elder, today the Agro Pontino in Italian, is an approximately quadrangular area of former marshland in the Lazio Region of central Italy, extending along the coast southeast of Rome about 45 km (28 mi) from just east of Anzio to Terracina (ancient Tarracina), varying in distance inland between the Tyrrhenian Sea and the Volscian Mountains (the Monti Lepini in the north, the Monti Ausoni in the center, and the Monti Aurunci in the south) from 15 to 25 km (9.3 to 15.5 mi). The northwestern border runs approximately from the mouth of the river Astura along the river and from its upper reaches to Cori in the Monti Lepini.
The former marsh is a low tract of mainly agricultural land created by draining and filling, separated from the sea by sand dunes. The area amounts to about 80,000 ha (800 km2; 310 sq mi). The Via Appia, a Roman military road constructed in 312 BC, crosses the inland side of the former marsh in a long, straight stretch flanked by trees. Before then, travelers had to use the Via Latina along the flanks of the mountains; Terracina could not be reached across the marsh.
Further southward along the coast as far as Minturno is another stretch of former coastal marsh called the South Pontino, the largest section being between Terracina and Sperlonga, as far inland as Fondi. It was part of ancient Latium adiectum and still belongs to Lazio. Bordered by the Aurunci Mountains, this land is mainly reclaimed, as well, but the more frequent incursion of hills permitted more dense settlements. Leaving Terracina, the Via Appia crosses it, as well.
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