The single-vehicle collision happened on the C1s Old Military Road between Castle Douglas and Dumfries at about 8.55pm on Wednesday.
Emergency services attended, but the 23-year-old male driver of the white Vauxhall Vivaro was pronounced dead at the scene.
Police Scotland said his next of kin have been made aware.
The force said three dogs were in the van. One was euthanised due to its injuries, while the other two were taken to a local veterinary practice for treatment.
The road was closed for investigation works and reopened at about 2.50am on Thursday.
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Sergeant Colin Ramage said: “Our thoughts are with the family and friends of the man who has died.
“Enquiries are ongoing to establish the full circumstances of the crash, and we would urge anyone who saw what happened to come forward.
“We’re also keen to speak to anyone who was driving in the area around the time of the crash and may have dashcam footage, as it could assist our investigation.”
