The Neckar-Odenwald Limes (German: Neckar-Odenwald-Limes) is a collective term for two, very different early sections of the Upper Germanic-Rhaetian Limes, a Roman defensive frontier line that may have been utilised during slightly different periods in history. The Neckar-Odenwald Limes consists of the northern Odenwald Limes (Odenwaldlimes), a cross-country limes with camps, watchtowers and palisades, which linked the River Main (Latin: Moenus) with the Neckar (Latin: Nicer), and the adjoining southern Neckar Limes (Neckarlimes), which in earlier research was seen as a typical 'riverine limes' (German: Nasser Limes; Latin: limes ripa), whereby the river replaced the function of the palisade as an approach obstacle. More recent research has thrown a different light on this way of viewing things that means may have to be relativized in future. The resulting research is ongoing.
The Odenwald Limes begins in the north on the River Main, either near Obernburg or near Wörth, and runs southwards from there, skilfully using the topographical features of the Odenwald highlands, to the River Neckar, which it probably reached in the area of the present-day county of Heilbronn. The Neckar line forms its extension in a southerly direction as far as Arae Flaviae in the terrain of the present town of Rottweil, where it oriented itself to the course of the river.
The Neckar-Odenwald Limes probably emerged in the area of the Odenwald Limes during the Trajan period and, in the area of the Neckar line, in the Domitian or Early Trajan period, and, in the area of the old Neckar camps, in the Vespasian period. It went through several rebuilding phases and did not become obsolete until the construction of the almost perfectly straight Anterior Limes (Vorderer Limes) in the years between 159/161 and 165.