HDN
# HDN

HDN may refer to

## Medicine

* Hemolytic disease of the newborn, an alloimmune illness
* Hydronephrosis, hydrostatic dilation of the kidney

## Places

* Harlesden station, England, station code
* Yampa Valley Airport, Colorado, US, IATA code

## Other

* Hyperdimension Neptunia, a video game series
* Hydrodenitrogenation, an industrial chemical process
* Northern Haida language of North America, ISO 639-3 code
* Philippine Human Development Network
* Hdn., an abbreviation for the Greek grammarian Aelius Herodianus
