The fair place to meet is Albuquerque, NM — the city closest to the midpoint of Denver and Salt Lake City. From the farther side that’s about 10 hr 10 min of driving.
Recommended midpoint
Albuquerque, NM
From Denver
7 hr 1 min
334 mi to Albuquerque
From Salt Lake City
10 hr 10 min
485 mi to Albuquerque
Denver has the shorter trip; the split is off by about 3 hr 9 min. The alternatives below can even it out. Denver and Salt Lake City are about 371 miles apart.
Denver and Salt Lake City are about 371 miles apart by road. Split the difference and you arrive near Albuquerque, the city closest to the halfway point between them. That puts roughly 7 hr 1 min of driving on the Denver side and 10 hr 10 min on the Salt Lake City side — the fairest single meeting point among the cities near the middle.
That's a half-day drive from each side, so Albuquerque suits an overnight or a weekend rather than a quick coffee — long enough to want a reason to stay, short enough to drive.
If Albuquerque doesn't have what you're after, Las Vegas and Boise are also close to the midpoint and worth a look — each keeps the drive reasonably balanced between Denver and Salt Lake City.
Albuquerque is the most populous city in the U.S. state of New Mexico. Founded in 1706 as La Villa de Alburquerque by Santa Fe de Nuevo México governor Francisco Cuervo y Valdés, and named in honor of Francisco Fernández de la Cueva, 10th Duke of Alburquerque… Read more →
Denver is the capital and most populous city of the U.S. state of Colorado. Officially a consolidated city and county, it is located in the South Platte River valley on the western edge of the High Plains, and is just east of the Front Range of the Rocky… Read more →
Salt Lake City, often shortened to Salt Lake or SLC, is the capital and most populous city of the U.S. state of Utah. It is the county seat of Salt Lake County, the most populous county in the state. Read more →
City descriptions adapted from Wikipedia (CC BY-SA); photos via Wikimedia Commons, credited above.
Estimates use straight-line distance and typical road speeds; real drive times vary with route and traffic.