thumb|World War II memorial at Onsøy thumb|Onsøy Church thumb|Elingaard Manor Onsøy is a peninsula and a former municipality in Østfold county, Norway. The administrative centre was Gressvik.
thumb|World War II memorial at Onsøy thumb|Onsøy Church thumb|Elingaard Manor Onsøy is a peninsula and a former municipality in Østfold county, Norway. The administrative centre was Gressvik.
==History== The parish of Onsø was established as a municipality January 1, 1838 (see formannskapsdistrikt). A part of Onsøy with 170 inhabitants was moved to the neighboring municipality Fredrikstad on 1 January 1968.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).