In Word Ways in November 1973, Dmitri Borgmann searched for names of U.S. Cities, towns, or villages that were transposals of each other. The longest well-mixed pair he found consisted of 9-letter names: MASTERSON, Texas, and SEARSMONT, Maine. It is worthwhile to revisit this topic in hopes of finding longer examples.
"Transposals Between U.S. Place Names,"
Word Ways: Vol. 52
, Article 25.
Available at: https://digitalcommons.butler.edu/wordways/vol52/iss4/25