The likelihood of having an abortion in the U.S.A. is strongly dependent upon where a woman lives. Abortion rates vary markedly from state to state, and these variations have been increasing, especially in recent years. Path analysis shows the causal structure of public demand and access variables that determined state abortion rates in 1991 and 1992. Access variables, including the restrictiveness of state laws regulating abortion, state funding of abortions for poor women and the availability of hospital abortions, affect abortion rates directly. Greater accessibility leads to higher abortion rates. Public demand variables affect abortion rates both directly and indirectly through access conditions. The number of women at risk of unintended pregnancies leads to higher abortion rates directly and indirectly through its effects on medical access. Per capita income, percent Catholic, and percent of the population born outside the state affect abortion rates indirectly through the access variables. High per capita income leads directly to greater availability of hospital abortions, higher levels of state funding of abortions for poor women, less restrictive state abortion laws, and indirectly to higher abortion rates. States with large non-native populations have less restrictive abortion laws and higher abortion rates. The presence of a large Catholic population reduces the number of hospitals offering abortion services and leads indirectly to lower abortion rates. The interaction of public demand and access at the state level creates geographically varying environments in which abortion decisions are made.