Hydrochus elongatus
- kingdom: Animalia
- phylum: Arthropoda
- class: Insecta
- order: Coleoptera
- family: Hydrochidae
- genus: Hydrochus
- species: Hydrochus elongatus
- Zurndorf
Burgenland- Biedermannsdorf
- Groß-Enzersdorf
- Laxenburg
Lower Austria- Wundschuh
Styria
Austria- Sauverny
B9
France- Karlskrona
Blekinge- Leksand
Dalarna- Fjärås kyrkby
- Vallda
Halland- Bor
Jönköping- Nybro
Kalmar- Ljunghusen
- Lund
Skåne- Djursholm
Stockholm
Sweden- Sankt Margrethen
Saint Gallen
Switzerland- Addlestone
- Askern
- Botesdale
- Bradley
- Charvil
- Cheam
- Chertsey
- Claydon
- Cliffe
- Cooling
- Copmanthorpe
- Cottenham
- Crowle
- Deal
- East Boldon
- Egham
- Elstead
- Exminster
- Gainsborough
- Greenford
- Harrow
- Harrow on the Hill
- Highbridge
- Histon
- Hook
- Howden
- Ipswich
- Malmesbury
- Morden
- Northolt
- Pevensey
- Scarborough
- South Benfleet
- Stalham
- Stone
- The Boldons
- Twyford
- Upton
- Waltham
- Wargrave
- Wedmore
- West Hallam
- Weston-super-Mare
- Wigston Magna
England
United Kingdom