There are no towns halfway between a single place.
Lavonia, Georgia, is halfway between those two towns.
Parkton, MD
Assuming you mean what town is halfway between Denver and Galveston. A small town named Childress is halfway, but the closest larger towns are Amarillo or Wichita Falls
There aren't many towns on that whole stretch of I-5. Wasco is the closest to halfway.
Longview TX or Marshall TX
New England, ND
Harrisonburg and Staunton, Virginia
Philadelphia is the city that is halfway between Washington DC and Boston MA. New York and Baltimore are the other towns that are in between.
Timaru is closest town to halfway between the two towns. It is 167 km from Christchurch and 192 km from Dunedin .
The most notable towns halfway between Biloxi and Atlanta are Greenville Alabama and Mongomery Alabama.
The halfway point would be either Milesburg or Bellefonte, PA. The two towns are right next to each other.