heartland

noun6

1. •
   The interior part of a region, especially when contrasted with coastal parts or when regarded as particularly powerful or significant.
2. •
   In the geopolitical theory of the English geographer Halford John Mackinder (1861–1947): the interior of the world island comprising north-central Eurasia regarded as politically powerful.
3. •
   [before a noun] (US) The states in the centre of the United States, chiefly regarded as politically and socially conservative; also, the people living in such states collectively.
4. •
   A region or part of a region particularly associated with or significant for a characteristic, such as an activity, a faith, support for a political party or other organization, etc.

   • The home counties are the Conservative heartland.
   • We stayed in the heartland of the French wine-growing regions.
5. •
   [in the plural] (Singapore) Residential districts and planning areas outside the city centre; the new towns of Singapore collectively.

   • Those in the HDB [Housing and Development Board] heartland will be able to vote in the airconditioned comfort of their community centres […] — 2003
6. •
   Synonym of heart (“the seat of the affections or love”).