The map was drawn and signed almost exactly 252 years ago by a Spanish explorer named Miguel Costanso. The original manuscript map of coastal California is estimated to be worth between $600,000 and $800,000 by Bonhams, the auction house selling the relic in New York.
In a statement shared with SFGATE the auctioneers characterize the item as "the most important 18th century map of California."
As part of the historic Portola expedition — the first time European settlers set foot in California — Costanso acted as an engineer while on land, and a cartographer at sea. The map, drawn in Mexico and signed by Costano on Oct. 30, 1770 details the inlets of the bay and North Bay, and alongside San Francisco, also names Point Reyes and the Farallones. Bonhams says the previous map drawn from the same expedition did not include the Bay Area.
Indigenous people lived in what is now California up to 19,000 years before the Europeans settled in the region. The Portola expedition of 1769-1770 marked a pivotal moment in the Spanish colonization of the Pacific Coast, that would result in the establishment of 21 missions throughout California in the following years, including four in the Bay Area. Tens of thousands of indigenous people would be killed over the following century by European settlers in what is now recognized as the California genocide.
The square map measures approximately 33 inches by 33 inches on four adjoined sheets, with minimal damage except some wear at the folds, Bonhams says. The item will be auctioned in New York and online on Oct. 25. If you have the best part of a million dollars to spare, log on to the Bonham's site to place your bid.
