CONTEXT: Unintended pregnancy is a key reproductive health indicator, but rates have never been calculated for all 50 states. METHODS: State‐level estimates of unintended pregnancy rates in 2006 were calculated using data from several sources. The proportion of births resulting from unintended pregnancies was obtained from the Pregnancy Risk Assessment Monitoring System and similar state surveys, and the intention status of pregnancies ending in abortion from a national survey of abortion patients. These proportions were applied to birth and abortion counts for each state, and fetal losses were estimated. Rates of unintended pregnancy were obtained by dividing relevant figures by the number of women aged 15–44 in each state. Six states and the District of Columbia had no appropriate survey data; their rates were predicted using multivariate linear regression. RESULTS: In 2006, the median state unintended pregnancy rate was 51 per 1,000 women aged 15–44. Most rates fell within a range of 40–65 unintended pregnancies per 1,000 women. The highest rate was in Mississippi (69); the lowest rate was in New Hampshire (36). Rates were generally highest in the South and Southwest, and in states with large urban populations. In 29 states and the District of Columbia, more than half of pregnancies were unintended; in nine, a consistent upward trend in unintended pregnancy rates between 2002 and 2006 was apparent; no state had a consistent decline. CONCLUSIONS: These rates provide benchmarks for measuring the impact on unintended pregnancy of state policies and practices, such as those governing sex education and the funding of contraceptive services.