The drive from Billings to Sioux Falls is approximately 750 miles. You will travel east on I-90 across the entire state of South Dakota. The journey takes about 11 to 12 hours. You will pass through the plains and the Black Hills. This route is a major cross-country path.
Total Distance: 1200 km driving, 1050 km air.
Watch for wildlife on the plains.
Summer and early autumn for the best weather.