Concourse A at Detroit (DTW) and Concourse D at Miami (MIA) are two of the longest airport concourses in the United States; each is just under a mile long.
Overlaying both of them at the same scale (and rotating them to align), MIA Concourse D appears to be slightly longer if MIA’s small jet piers on the left side of the image are included. Even if they aren’t included, the walking distance in MIA is longer due to the two bends in the concourse.