These five consolidated volumes constitute a surname index, with corresponding microfilm locations, to the residents of the Pennsylvania counties of Berks, Bucks, Lancaster, Luzerne/Wyoming, and Northampton respectively, in the year 1850. (Wyoming County was formed from Luzerne in 1842.) Although it was not possible, for reasons of economy, to list every person appearing in the census by given name, each book lists all the surnames appearing in the census for the county(ies) in question (i.e., Berks, 7,000; Bucks, 8,000; Lancaster, 15,000; Luzerne/Wyoming: 10,000; and Northampton, 5,000). The arrangement of each volume is alphabetical by surname, with corresponding code numbers keyed to the borough or township and to the house numbers within the borough or township in which were residing individuals of a particular surname. Thus, for purposes of obtaining a copy of the original census page, both the area number and the house number are conveniently specified.