A Frontier People Group (FPG) is an Unreached People Group (UPG) with virtually no followers of Jesus and no known movements, still needing pioneer cross-cultural workers. Joshua Project approximates FPGs as 0.1% or fewer Christian Adherents and no confirmed, sustained movements to Jesus.

**One-fourth of the world lives in these FPGs and have almost no chance of hearing about Jesus from someone in their own people group. About HALF the population of all FPGs live in just 36 people groups, each over ten million in population. Frontier People Groups (FPGs) are a subset of unreached people groups (UPGs). FGPs are defined as UPGs with 0.1% (1 in a 1000 people) or fewer who identify with Jesus in any way. These are the “most unreached of the unreached.” 

Source: Joshua Project. Go here for the most recently updated numbers.