If the spelling of Hagaberg is correct (and is not Hageberg or Högeberg or Högsberg or Hagberg), then Hagaberg is a gård = farm in Lofta parish, Kalmar county, Sweden. I found this location on the Rosenberg CD, made from a book about Swedish place names written in the 1880s.
"Hagaberg. Gård i Lofta sn, N. Tjusts hd, Kalmar län, vid Gamlebyviken."
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