Out in the far reaches of Long Island lies the town of Bridgehampton. This name, being a fairly long isogram, has often caught my attention in my periodic perusals of various atlases. It is, as far as I know, the longest solidly written placename isogram in the United Sates.
Word Ways: Vol. 29
, Article 2.
Available at: http://digitalcommons.butler.edu/wordways/vol29/iss4/2