Almost five million women were enrolled in family planning clinics in the United States in 1983, eight percent more than in 1981. The number of family planning provider agencies declined slightly, from 2,504 to 2,462, but the number of clinic sites that could be identified increased slightly, from 5,124 to 5,174. Family planning clinics operate in three-quarters of U.S. counties; in 1975, the last time county coverage was checked, four-fifths of the counties had clinics. About one in 20 women who are exposed to the risk of unintended pregnancy and live in unserved counties are teenagers or low-income women. Nonmetropolitan counties are more likely to be without clinics than are metropolitan counties. Overall, there are 417,000 low-income women and 249,000 teenagers at risk of unintended pregnancy living in counties where there are no family planning clinics. In 1983, health departments constituted six in 10 of all family planning agencies and served two-fifths of all family planning clinic patients; Planned Parenthood affiliates accounted for fewer than one in 10 agencies and served more than one-quarter of all patients. Hospitals and all other agencies served about one-third of the total 1983 caseload. These patterns were similar to those reported for 1981. Family planning clinics continue to serve primarily low-income women: Four-fifths of the nearly five million clinic patients in 1983 had family incomes below 150 percent of the federally defined poverty level. About 1.6 million women aged 19 and younger were served, representing one-third of all clinic patients in 1983.(ABSTRACT TRUNCATED AT 250 WORDS)