The 1840 Census
This link accesses the 195 pages of census data from the city of Lowell in 1840 -
"United States Census, 1840," database with images, FamilySearch, Massachusetts > Middlesex > Lowell > image 1 of 195; citing NARA microfilm publication M704, (Washington D.C.: National Archives and Records Administration, n.d.).
The link below accesses a filtered search of the FamilySearch database of the 1840 census using the search criteria of "Lowell, MA" and "1840" -
https://www.familysearch.org/search/record/results?count=20&q.anyPlace=Lowell%2C%20MA&q.anyPlace.exact=on&f.collectionId=1786457
