In 1878, the town was renamed from Dahlen to Rheindahlen in the Prussian Province of Düsseldorf by order of Emperor William I.

It lies to the south-west of the main urban area and borders on the municipality of Schwalmtal to the west and the county of Heinsberg to the southwest.

Its neighbouring communities within the borough of Mönchengladbach are Hardt to the north, Rheydt to the east and Wickrath to the south.

It is situated on the southern edge of the Lower Rhine Plain on the Schwalm-Nette Plateau which, in the western part of the borough is characterised by wetlands and woods.

The Rheindahlen landscape lies on the southern edge of the Mönchengladbach Loam Plain and rises towards the south.

In some cases, the drainage even causes movements on the otherwise inactive geological faults which subdivide the Lower Rhine Bay.

[3] The former borough of Rheindahlen (since 2009 Mönchengladbach West) consists of the nine districts of Wickrath-Mitte, Wickrath-West, Wickrathberg, Wanlo, Hehn, Holt, Hauptquartier, Rheindahlen-Land and Rheindahlen-Mitte.

[6] Rheindahlen is also an extremely rich site for fossil remains that have survived in the soil which is mainly clay.

[7] In the recent past, in the southern part of the borough, near an old brickworks, archaeological excavations took place that have contributely decisively to the understanding of the hunting and settlement areas of Neandertal man.

[8] A thirteen-fold enlarged bronze replica of the hand hammer found in 1994 has been on display in the centre of Rheindahlen since 2003; it recalls the early history of the village.

[10] Clues as to Roman settlements were found inter alia at Genholland, Genhülsen, Griesbarth, Hilderath, Merreter and Peel, including a 2nd-century, metre-high matrona stone discovered in 1961[11] and probably the remains of a road.

Due to the number of places with the name Dahl, Dalheim, Dalem and Dalhem it became increasingly difficult for postal services, which began around 1870, to distinguish between the individual settlements.

The then Lord Mayor of Gladbach, Hermann Piecq planned the incorporation of Neuwerk, Gladbach-Land and Rheindahlen.

Another indication that Dalon was not the later Dahlen is reinforced by the fact that neither in the present day Rheindahlen itself nor the surrounding villages have any traces from the time of the Carolingians or the Merovingians been found.