Regionalization is the process by which governing entities come together to combine previously separate areas for more uniform control, such as water districts, land heritage areas, etc. This is not always a good idea because it removes control much further away from the people it governs and the people who pay the taxes to support it.
It depends a lot on who is doing this and why. Some areas are formed that previously had no governing authority, thus creating one for themselves. Others that have direct input from the voters such as two small towns combining fire departments are more transparent.