It is difficult to tell how common HD is in a population. In Western countries it's estimated that about five to seven people per 100,000 are affected by HD. There are a few isolated populations in Western Europe where HD is unusually common.
A very high concentration of HD has also been found in the Lake Maracaibo region of Venezuela where the prevalence of HD is about 700 per 100,000.
Australia and New South Wales and ACT
In Australia over 1,800 people have HD and approximately 9,000 are at risk. For NSW this equals around 600 and in the ACT around 40 people with HD. There are people with HD in all NSW regions, but prevalence may be higher around the Cenral Coast and Hunter regions.