When Jesus commanded His followers to "make disciples of all the nations" in Matthew 28:18-20, He was not referring to political nations. The word Jesus used for nations in Greek is "ethne" from which we get the English word "ethnic". An unreached people group is "a people group within which there is no indigenous community of believing Christians able to evangelize this people group". It means that there is no known active on-site church planting effort underway and few if any know believers. It also means there are definitely no missionaries, in all likelihood no outreach, no church or fellowship of believers, no Christian materials, and few if any Bibles in these people groups. It is a great injustice to think that 2000 years after Jesus gave the Great Commission that many people groups have no witness in their midst. While it is certainly possible the Lord has supernaturally appeared to and been at work among an unreached group without outside involvement, this would not be the typical way He has ordained for the spread of the Gospel. He commanded the Church to go.