The statistics presented in this bulletin showing workers classified by major occupation groups and class of worker are limited to employed workers, that is, persons 14 years old and over who were actually at work or who had a job in the week of March 2.1 to 30, 1940.
The occupation statistics presented in this bulletin are in terms of 10 major groupings of the 451 specific occupation titles of the 1940 classification system used by the Bureau of the Census. It may be noted that the occupations Farmers (owners and tenants) and Farm managers are included in the major occupation group Proprietors, managers, and officials; and that the occupations Farm laborers (wage workers) and farm foremen and Farm laborers (unpaid family workers) are included in the major occupation group Laborers.

A dwelling unit is defined as the living quarters occupied by, or intended for occupancy by, one household. A dwelling unit may be a detached house; a tenement, flat, or apartment in a larger building (apartment house, apartment hotel, or section of a hotel devoted entirely to apartment rather than transient use); or a room in a structure used primarily for business or other nonresidential purposes. It may be a tourist cabin, trailer, railroad car, boat, etc., if occupied by person having no other place of residence.