Policy projections and recent research suggest that large numbers of irregular migrants from sub-Saharan Africa will continue to attempt to make their way to Europe over the next few decades. In response, European countries have made and continue to make significant investments in information campaigns designed to discourage irregular African migration. These campaigns are frequently accompanied by evaluations of some sort but, to our knowledge, none have involved a well-powered randomized controlled trial with a representative sample and actual migration as an outcome. We report results from such a field experiment that we implemented in 2020 and 2021 with 3200 households in Edo and Delta states in Nigeria, in which treated households received detailed, accurate information about features of the journey along the "Mediterranean route." We estimate effects of this information on beliefs about migration-related risks, interest in attempting irregular migration, and actual migration from treated households, using data from a midline conducted six months after treatment and an endline after twelve months.