ONE OF THE RAREST OF ALL INDEPENDENT MAIL USAGES FROM THE ONLY STEAMBOAT CARRIER TO ISSUE STAMPS.
Prince's Letter Dispatch was established by J. H. Prince of Portland Me. and carried mail by steamboat to Boston, which is probably why it continued to function without government interference as late as 1869. The pictorial stamps used by Prince were engraved and printed by Lowell & Brett of Boston (Lowell's imprint appears below the steamboat vignette). Although an abundant supply of unused stamps reached philatelic hands, genuinely used stamps are extremely rare, and only eleven covers are recorded by Larry Lyons (Penny Post, October 2002; one or two of the listings are questionable covers). This is one of the earliest of the recorded covers (an Aug. 1864 cancel on an off-cover stamp is known). Some of the later usages are known with a blue oval company handstamp.
Ex Golden (Siegel Sale 817, lot 1451, realized $7,500 hammer). With 1982 P.F. certificate