"And Jesus came and said to them, “All authority in heaven and on earth has been given to me. Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.” (Matthew 28:18-20)
To learn more about URCNA missions you can read "The Trumpet: Newsletter of the URCNA" here.
Here is a list of URCNA missions and church plants in North America.
Here is a list of foreign URCNA missions and church plants.
Here is a list of other mission works (prison ministry, international Reformed seminary training, and chaplains).