USCMA has compiled the following missionary information from data forms received from mission-sending groups and home dioceses -- with additional reference to The Official Catholic Directory.   The current statistics are from the survey done in 2007. 

These are, therefore, as reliable as the most diligent effort can make them and as the constant changes in personnel allow.

U.S. Catholic Mission Handbook
Field Distribution of U.S. Catholic Missioners
U.S. Catholic Missioners By Role
Primary Ministry Work Activity
U.S. Missioners Serving in U.S. in Cross Cultural Mission

The lists of data include only U.S. missionaries, which means those who are or have been United States citizens by birth or naturalization.  Those who have taken out citizenship in their country of mission service are still listed here as missionaries from the Unites States. On the other hand, citizens of other countries serving as members of mission-sending groups headquartered in the U.S. are not listed.

As an example, there are numerous Maryknoll sisters serving abroad, often in countries other than their homeland who are not U.S. citizens and therefore are not listed here among the Maryknoll sisters serving as U.S. Catholic missionaries abroad.  This policy helps to prevent overlapping when the various national mission councils publish their tabulations.

It must be remembered, however, that mission-sending groups which appear to have only very few members in a given mission field may have many more who are not of U.S. Citizenship.

The lists bear the heading U.S. Catholic Missionaries. This includes all those Catholics who are sponsored by Catholic mission-sending agencies, even if they work for projects not sponsored by the Catholic Church.

The term "missionaries / missioners" is used in its generally accepted sense. It includes not only those engaged in the primary and subsequent stages of evangelization but also those in closely related areas of community service and development.

The term "serving" ordinarily stands for service over a period of years. While some groups provide opportunities for short-term service, only those individuals are included in these statistics who serve for a minimum of one year.

The term "abroad" means outside of the 50 United States. The present tabulation does not include, therefore, the many "home missioners" and those working in cross-cultural situations in the U. S.  Those working in Alaska and Hawaii are not included in this data as they were in previous surveys.  Recent political shifts have enabled a renewed mission effort in Eastern Europe.