It's more than an hour and a half away from Canberra in an isolated part of the Namadgi National Park.
Yet somehow vandals have trashed the heritage-listed Orroral Homestead, after parks authorities and volunteers spent more than a decade restoring it.
ACT Parks and Conservation regional manager Brett McNamara said while the 29 smashed window panels will cost hundreds of dollars to fix, it would also cause "pain and anxiety" to the volunteers who spent thousands of hours rebuilding the homestead.
"It was very much a deliberate act. In the 30 years I've been with the parks services it's the first time that I can recall any direct vandalism at Orroral Homestead," Mr McNamara said.
"I can only describe it as at truly magnificent homestead and it's quite disappointing.
"It's certainly a one-off and we hope by bringing this to the attention of the greater Canberra community people with information might be able to come forward. We don't want to see this happen into the future."
Orroral Homestead was built in the mid-19th century for graziers for Archibald and Mary McKeahnie.
After a push in the mid-1980s by the national parks' association, volunteers and parks authorities spent more than 10 years returning it to its former glory.
Mr McNamara estimated "hundreds if not thousands of people" visited the Orroral Valley each year.
While the homestead is off a public road, Mr McNamara said it was quite "isolated".
"The valley is also the site of the former deep space tracking station and close by is also Indigenous artworks and artefacts so the Orroral Valley speaks about the human influence on that landscape from Ngunnawal to NASA," Mr McNamara said.
You can report suspicious activity in the ACT's national parks through Access Canberra.