heartland
noun [ C ]
uk/ˈhɑːtlænd/ us(also heartlands [ plural ]) POLITICS
an area where a large number of people support a particular political party and vote for it in an election:
Turnouts were as low as 14% in parts of the so-called heartland.
the Labour/Tory/Republican heartland(s)
an area where a particular industry is very important:
heartland of sth Poland, the Czech Republic, and Slovakia have become Europe's new heartland of carmaking investment.
agricultural/industrial/commercial heartland(s) At the center of India's industrial heartland, the hoped-for flood of jobs has not yet come.