The fair place to meet is Denver, CO — the city closest to the midpoint of Chicago and San Diego. From the farther side that’s about 19 hr 15 min of driving.
Recommended midpoint
Denver, CO
From Chicago
19 hr 15 min
918 mi to Denver
From San Diego
17 hr 28 min
833 mi to Denver
San Diego has the shorter trip; the split is off by about 1 hr 47 min. The alternatives below can even it out. Chicago and San Diego are about 1,732 miles apart.
Chicago and San Diego are about 1,732 miles apart by road. Split the difference and you arrive near Denver, the city closest to the halfway point between them. That puts roughly 19 hr 15 min of driving on the Chicago side and 17 hr 28 min on the San Diego side — the fairest single meeting point among the cities near the middle.
Over this distance most people will fly rather than drive the whole way. Denver still makes a fair, central place for Chicago and San Diego to converge, splitting the travel instead of asking one side to cross the country.
If Denver doesn't have what you're after, Albuquerque and Oklahoma City are also close to the midpoint and worth a look — each keeps the drive reasonably balanced between Chicago and San Diego.
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 →
Chicago is the most populous city in the U.S. state of Illinois and in the Midwestern United States. Located on the western shore of Lake Michigan, it is the third-most populous city in the United States, with a population of 2.74 million at the 2020 census. Read more →
San Diego is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. It is the eighth-most populous city in the U.S. 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.