How many miles long is the U.S. from the Pacific to the Atlantic?

Answer 1

Approximately 3,000, depending upon where you measure from and to.

Answer 2

Being an extremist, I had to go -- to the extreme! From the most extreme easterly point, West Quoddy Head, Maine to the most westerly point, Cape Wrangell, Alaska (Attu Island), is 4045 miles (okay, you can argue Alaska is not contiguous, but that was not the question, was it? And, yes, Attu Island is farther west than Hawaii is.)