I think you are looking for a work for it - and this word is "megalopolis"
Some examples of a megalopolis are:
A Taiheyo belt in Japan (with Tokio and Osaka)
Northeast Megalopolis with New York and Boston
Yangze River Delta in China
<h2>Political science </h2>
It is a social psychology which administers with arrangements of governance, and the interpretation of federal movements, governmental decisions, and legislative actions. It traffics extensively with the principles and application of diplomacies which is usually thought of as ascertaining of the concentration on powers and sources.