The night sky above parts of Wiltshire, Dorset, Hampshire and Somerset has been designated an international dark sky reserve.
Cranborne Chase Area of Outstanding Natural Beauty (AONB) is only the 14th such area in the world to be certified.
The status is awarded by the International Dark-Sky Association (IDA) to areas which offer "exceptional starry skies".
It is the first AONB in the country to be designated in its entirety.
The IDA status, which took Cranborne Chase AONB 10 years to achieve, means controls are in place to prevent light pollution.
"We think of our beautiful landscapes as being on the ground, but 50% of our landscape is above our heads, in the sky," said Linda Nunn, director of Cranborne Chase AONB.
"Here in Cranborne Chase we can see the Milky Way and the Andromeda Galaxy, if the clouds allow.
"The AONB has pledged to protect and improve its dark sky for future generations.
"There are huge benefits for nocturnal wildlife, our own human health and wellbeing, for education, tourism and for energy saving. We're thrilled to be playing our part."
Cranborne Chase AONB is the sixth largest AONB in the country. Covering 981 sq km (380 sq mi), it straddles parts of Wiltshire, Dorset, Hampshire and Somerset.
Adam Dalton, from the IDA, said: "It has the largest central area of darkness of any international dark sky reserve in the UK.
"For those living and visiting this beautiful area, this is something to be celebrated and enjoyed."