Census records are available for some areas in the Rheinland. Check the Family History Library catalog by doing a key word search for your town of interest. Also, you may do a keyword search by "Roer Canton" and you will get a list of many populations lists covering the Rheinland and parts of the Netherlands.
See catalog search for "de la Roer"
Gen Wiki lists of population registers for "de la Roer": http://wiki-de.genealogy.net/Kreisarchiv_Neuss/Bev%C3%B6lkerungslisten_1794-1815
Grevenbroich census records 1890 available at this link [includes Allrath, Barrenstein and Neuenhausen: https://wiki.genealogy.net/Grevenbroich/Volksz%C3%A4hlung_1890