The easternmost land battle was probably Williamsburg, Va., and the westenmost was Picacho Peak, about 40 miles west of Tuscon, Ariz. The westernmost contact was apparently at Stanwix Station, on the Gila River near present-day Dateland, Ariz. These all took place in 1862. The distance between Williamsburg and Tucson is about 2300 miles.
The other thing I found out about Texas is that from eastern border to western border is the same distance as from NYC to Chicago. Also, France is almost the same size as Texas.