This report describes homegrown violent jihadists and the plots and attacks that have occurred since 9/11. For this report, "homegrown" describes terrorist activity or plots perpetrated within the United States or abroad by American citizens, legal permanent residents, or visitors radicalized largely within the United States. The term "jihadist" describes radicalized individuals using Islam as an ideological and/or religious justification for their belief in the establishment of a global caliphate, or jurisdiction governed by a Muslim civil and religious leader known as a caliph. The term "violent jihadist" characterizes jihadists who have made the jump to illegally supporting, plotting, or directly engaging in violent terrorist activity. The report also discusses the radicalization process and the forces driving violent extremist activity. It analyzes post-9/11 domestic jihadist terrorism and describes law enforcement and intelligence efforts to combat terrorism and the challenges associated with those efforts. Appendix A provides details about each of the post-9/11 homegrown jihadist terrorist plots and attacks.