The South Jutland police said on Twitter that the queues started building at the Frøslev border post immediately after midnight, when Denmark opened up to residents of Germany who have a holiday booking in Denmark.
They then grew over the night, reaching 8km in the early morning, and then reducing to a delay of about 15 minutes by 9am.
“Here comes the dawn!” they wrote on Twitter. “Now there's a 7-8 km moving queue at the motorway at Frøslev. A 1km queue at Kruså.”
Denmark on Monday opened its borders to holidaymakers from Germany, Norway and Iceland, so long as they have a booking of at least six days at a hotel, campsite or holiday cottage in the country.