Nordsee-Treene is an Amt ("collective municipality") in the district of Nordfriesland, in Schleswig-Holstein, Germany. Its seat is in Mildstedt. It was formed on 1 January 2008 from the former Ämter Friedrichstadt (except the town Friedrichstadt), Hattstedt, Nordstrand and Treene.

Nordsee-Treene
Map of Nordfriesland highlighting Nordsee-Treene
Map of Nordfriesland highlighting Nordsee-Treene
CountryGermany
StateSchleswig-Holstein
DistrictNordfriesland
Region seatMildstedt
Government
 • AmtsvorsteherEva-Maria Kühl (CDU)
Area
 • Total
412.1 km2 (159.1 sq mi)
Population
 (2020-12-31)
 • Total
23,655
Websiteamt-nordsee-treene.de

The Amt Nordsee-Treene consists of the following municipalities:

  1. Arlewatt
  2. Drage
  3. Elisabeth-Sophien-Koog
  4. Fresendelf
  5. Hattstedt
  6. Hattstedtermarsch
  7. Horstedt
  8. Hude
  9. Koldenbüttel
  1. Mildstedt
  2. Nordstrand
  3. Oldersbek
  4. Olderup
  5. Ostenfeld
  6. Ramstedt
  7. Rantrum
  8. Schwabstedt
  9. Seeth
  1. Simonsberg
  2. Süderhöft
  3. Südermarsch
  4. Uelvesbüll
  5. Winnert
  6. Wisch
  7. Wittbek
  8. Witzwort
  9. Wobbenbüll

54°27′42″N 9°05′43″E / 54.461667°N 9.095278°E / 54.461667; 9.095278