The report is Vol. II of a series of 7 reports summarizing Illinois EPA's 1987 Volunteer Lake Monitoring Program (VLMP). It provides a program overview, summary of 1987 VLMP lakes in Northwestern Illinois, including a discussion of lake characteristics, volunteer participation, and a ranking of lakes on a regional basis. Northwestern Illinois results are compared to statewide statistics, and lake assessment information from the Illinois Water Quality Report 1986-1987 for Northwestern VLMP lakes is provided and briefly discussed. Lake/watershed management strategies are described. Eighteen volunteers recorded total depth, Secchi disc transparency, and field observations for 18 lakes in Northwestern Illinois between May and October, 1987. Included were 17 dammed-stream impoundments and 1 excavated lake. Average transparencies ranged from 7-128 inches. Fifty percent of the lakes exhibited average transparencies greater than 4 feet, 44 percent between 2 and 4 feet, and only one lake less than 2 feet. Two lakes were classified as mesotrophic, and the remainder, eutrophic, based on average Secchi disc transparency.