Latium adiectum or Latium Novum is an ancient Roman geographical term used at least as early as the 1st century AD, when mention of it occurs in Pliny in conjunction with Latium antiquum, the original territory of the Latini tribe. Says Pliny of the latter:

"Its inhabitants have often changed: at various times it has been occupied by various peoples - the Aborigines, the Pelasgi, the Arcades, the Siculi, the Aurunci, the Rutuli ...."

Then he speaks of a later extension to the river Garigliano, to include the Volsci, Osci and Ausones. The "last town" in the Adiectum Latium, or "Extension of Latium", was Sinuessa.