In order to determine the effect of rural industrial development in an historically rural area of Illinois, a stratified area probability sample survey of 781 household heads in an area experiencing limited industrial development and of 315 household heads in an area lacking industrial development was conducted in 1966. The results of this survey were compared with a similar 1971 survey (1,171 and 399 responses from the experimental and control areas respectively). Variables examined were: (1) Income (earnings and additional income of household heads and income of other household members); (2) Social Characteristics (% female-headed households, years of education, family size, status of current job, and age); (3) Group and Type of Income (female and male-headed households, farm and nonfarm households, household heads 65 years or older and those under 65 years); and (4) Social and Income Characteristics by Length of Residence. Findings indicated that development: (1) did not have a dramatic effect on level of income; (2) increased equality of income; (3) substantially and adversely affected the elderly; (4) adversely affect the average earnings of female household heads but positively affected female household heads but positively affected female income per dependent; (5) did not create a greater rate of in-migration (immigration appeared to increase median earnings and decrease income equality, as immigrants were of a higher socioeconomic strata). (JC)