We use unique data on abortions performed in New York State from 1971-1975 to analyze the impact of legalized abortion in New York on abortion and birth rates of non-residents. We find that abortion rates fell between 3 and 7 percent for every hundred miles a woman lived from New York in the years before Roe v. Wade and that the decline was greater for nonwhites than whites.  Our preferred estimates suggest that each abortion was associated with a decline of 0.93 births.  We predict that abortion rates would fall by 16 percent if Roe were overturned and 31 states banned abortion, resulting in 181,982 additional births or 4.2 percent of the U.S. total in 2007.  Under a less extreme scenario in which 17 states ban abortion, we estimate that abortions would fall by 6.6 percent resulting in 73,512 unintended births.