Why do some states grow faster than others? Economic research sheds some light on the subject. This article reviews and summarizes almost 100 publications related to this topic, primarily drawn from peer-reviewed, academic sources and government publications. The research suggests that social and cultural factors influence population trends just as much or more than state-level policies, so there are limits to what policymakers can achieve. But policy still does matter, especially for domestic in-migration. The research shows the importance of greater economic freedom for fostering local business activity and making a location a more appealing place to live.