I assume you mean by road. The road distance is about 572 miles. About 1/2 way would be exit 5 on the New Jersey Turnpike. The town near that exit would be Mt. Holly, New Jersey. Or did you wish a larger town? One that might qualify as an honest to God city? Philadelphia is very close to 1/2 way. Not quite 1/2 but close, about 273 miles from Virginia Beach depending on exactly where in Phily you were measuring from.
The halfway point between Iowa City, Iowa and Virginia Beach, Virginia is Maple Grove, Ohio. The closest major city that is about halfway is Columbus, OH.
West Virginia (Beckley and Charleston are the biggest cities in the area and are less than an hour apart)
Brooklyn IA
Craig, CO
A city halfway between Billings MT & Chicago IL could be Sioux Falls SD, depending on your route.
The city of Anchorage in Alaska is roughly halfway between Sydney and Chicago, in terms of distance. However, since there are no direct flights between Sydney and Anchorage, it may not be the most practical midpoint for travel purposes.
Philladaliphia
Chicago, Illinois and Atlanta, Georgia are 719 miles apart. A city located halfway between them would be Bonnieville in Kentucky.
Kalamazoo
Atlanta
Elk City, OK
Ragsdale, Arkansas.
Sioux Falls, South Dakota
North Royalton,OH
Memphis, TN