Alatri was a 2nd class distribution post office, reporting to Frosinone. In 1871, Alatri had a population of 13,841.
Alatri, September 16, 1847, stampless cover to Fumone, rated 1 bajocco for a letter within the same direzione postale. Frosinone straight-line transit marking on front, with an indistinct transit marking date applied at Frosinone on back.
Alatri, March 1864, 2 bajocchi black on greenish white 1852, pays the reduced 2 bajocchi rate effective January 1, 1864. Frosinone March 22, 1864 transit marking on front.