The halfway point between London in England (United Kingdom) and Annapolis in Maryland (US) is Bonavista.
Bonavista is in Canada.
Greensboro, NC is about halfway but it can depend on the route you take
John Town, MD.
The halfway point between Troy, MI and London KY falls in or around Vandalia, Ohio.
Batley
The halfway point between London in England (United Kingdom) and Aylesbury in England (UK) is Watford. Watford is in England (UK).
Silver Springs, OH is the halfway point.
Frankfort, IN
The halfway point between Melbourne and London is Akyab, Myanmar.
The halfway point is on I-87, just north of the NJ/NY state line, near Tuxedo Park, NY.
Bolingbroke, Georgia
Leeds in Yorkshire approx.
The geographic halfway point between London in England (United Kingdom) and Nottingham in England, (United Kingdom) is Northampton, also in England (UK). The halfway point co-ordinates are 52° 12' 8" N and 0° 55' 20" W.