An analysis combining individual-level data from the National Survey of Family Growth with aggregate-level information provides evidence that the characteristics of communities influence the contraceptive decisions of currently married white women in the United States. The analysis examined the relationship between the average effectiveness level of the contraceptive methods that a woman used over a three-and-a-half-year period and community characteristics such as employment opportunities, the availability of contraceptive and abortion information and services, and the level of religious adherence in communities. Community characteristics associated with higher levels of contraceptive effectiveness were rapid population growth, high rates of unemployment, elevated levels of religious affiliation, high socioeconomic status, and ready access to family planning information and services. Community liberality was negatively associated with effective contraceptive use. The results support arguments that various community characteristics affect a woman's contraceptive choices by increasing or decreasing the costs of an unintended pregnancy.