An air ambulance took one person to hospital while another was taken by regular ambulance after the incident at Ingleton.
North Yorkshire Police Roads Policing Group said this afternoon there was a road traffic collision on the B6255 near Newby Head Farm between Ingleton and Hawes.
The road is closed and will be for some time, the force said.
According to a social media post by the force, it has received help from North Yorkshire Fire and Rescue Service, Yorkshire Air Ambulance, Yorkshire Ambulance Service as well as West Yorkshire Police, Lancashire Police and Cleveland Police.
North Yorkshire Fire and Rescue service said a report came in shortly after 2.05pm.
"Crews from Hawes, Settle and an Officer were called to a serious road traffic collision," a spokesman said.
"One casualty was taken to hospital by air ambulance and one by road ambulance.
"Crews assisted with casualty care and made the scene safe."
North Yorkshire Police is yet to make an official comment.
More details to come.