Danish species per municipalities.

       
Red-veined Darter (Sympetrum fonscolombii)
Denmark
Status: First discovered in Denmark in 2003 and mainly in invasion years, like 2019, where numbers still only reached around a hundred or so individuals. Other years, like 2023, zero are found, while 2024 and 2025 showed good numbers (confirmed breeding on Amager both years). The pattern is similar in the rest of the north European region. The species is resident in the Mediterranean region.
Invasion years in Denmark: 2007+15+19+24.

Bornholm:
Mainly records from invasion year 2019 + 1 record 2025
Gribskov:
1 record Ellemosen 2019 (https://www.naturbasen.dk/observation?id=3043222)
Hillerød:
1 undocumented record s/Hillerød 2019 (https://www.naturbasen.dk/observation?id=3062100)
Horsens:
5 undocumented records 2019 (https://www.naturbasen.dk/observation?id=3080458)
Jammerbugt:
3 undocumented records Han Vejle 2019 (https://www.naturbasen.dk/observation?id=3146866)
Norddjurs:
Not seen Anholt
Nyborg:
1 undocumented record Tårup 2007 (https://www.naturbasen.dk/observation?id=178230)
Randers:
1 undocumented record 2019 (https://www.naturbasen.dk/observation?id=3080009)
Silkeborg:
2 undocumented records 2019 (https://www.naturbasen.dk/observation?id=3040022)
Skanderborg:
There is one record in naturbasen, https://www.naturbasen.dk/observation?id=3132857, but it looks like a sanguineum to me.
Skive:
2 undocumented records 2019 (https://www.naturbasen.dk/observation?id=3146866)
Svendborg:
1 undocumented record Tåsinge 2019 (https://www.naturbasen.dk/observation?id=3110711)
Tønder:
Also seen Rømø.
Vejen:
3 undocumented records Skærsø 2019 (https://www.naturbasen.dk/observation?id=3050238)
Syddanmark
Aabenraa
Esbjerg
Fredericia
Haderslev
Kolding
Langeland
Nordfyns
Nyborg
Odense
Svendborg
Sønderborg
Tønder
Varde
Vejen
Vejle
Ærø
Nordjylland
Aalborg
Frederikshavn
Hjørring
Jammerbugt
Thisted
Midtjylland
Aarhus
Hedensted
Herning
Holstebro
Horsens
Ikast-Brande
Norddjurs
Randers
Ringkøbing-Skjern
Silkeborg
Skive
Struer
Syddjurs
Østdanmark
Billund
Bornholm
Faxe
Gentofte
Gribskov
Guldborgsund
Halsnæs
Hillerød
Ishøj
Kalundborg
København
Lolland
Lyngby-Taarbæk
Odsherred
Rudersdal
Slagelse
Solrød
Sorø
Stevns
Tårnby
Vordingborg