Where did the “S” mintmark for San Francisco come from? 0

[RWB]

It was the idea of mint director James Ross Snowden as mentioned in this letter.

 I directed the Engraver some weeks ago to prepare dies. They will be made in time. The coins struck at this Mint have no particular mark on them; those struck at the Branch Mint are designated by a letter as follows – New Orleans, “O”; Dahlonega, “D”; Charlotte , “C”. I have instructed the Engraver to put [on] the letter “S” for the Branch at San Francisco.

[Excerpt from letter dated September 10, 1853 to James Guthrie, Sec. of Treasury from J. R.Snowden. RG104 E-11 Box 43 1850-53 San Francisco.]

Edited November 29, 2023 by RWB

[Henri Charriere]

And what explanation, pray tell, was offered in support of withholding the "P" mark for Philadelphia?

[RWB]

It was the only mint for 40+ years, so it needed no identifying mark. (Still doesn't.)

[Henri Charriere]

On 11/29/2023 at 7:25 PM, RWB said:

It was the only mint for 40+ years, so it needed no identifying mark. (Still doesn't.)

Unassailable logic.  You win.  Again.