The Filstrup cover, the only domestic use of the US 1860 90c stamp, will star as top lot in Robert A Siegel Auction Galleries' December 15 sale.
The sale is dedicated to the George J Kramer Collection of US domestic mails between 1776-1869, which charts the nation's early postal history. The cover, one of only six to feature the 90c stamp, is valued at $40,000-50,000.
The 90c stamp was the highest value of the 1851-1857 series, depicting a youthful George Washington in his military uniform. Issued in 1860, it saw limited use until August 1861, when all United States stamps were demonetarised at the start of the US civil war.
The remaining five covers are all addressed to foreign countries, making this the only example that remained in the United States.
Also starring in the auction is a superb series of mails from the nation's founders, with a free frank sent by Martha Washington from Mount Vernon expected to sell for $30,000-40,000.
Martha Washington was granted the franking privilege shortly after her husband's death in 1800, but used it for only two years before she died in 1802. There are just four reported free franks bearing her autograph, with Siegel describing the piece as "one of the greatest rarities of early American postal history and autograph collecting".
George Kramer has been a collector since 1975 and has won the highest national award, the American Philatelic Society's Champion of Champions, for his exhibits of "Wells Fargo & Company", "Across the Continent" and this collection. He has also written books on US stamps and contributed to The Pony Express, A Postal History.
Paul Fraser Collectibles has an exceptional collection of stamps for sale.