Was a mountain howitzer the first wheeled vehicle to cross America?

Dear Mr. History,

I have heard the first wheeled vehicle to cross North America was an early model of mountain howitzer, but been unable to find a reference to support this claim. Can you find support for this claim and, if so, what model of mountain howitzer was it?

Thanks,

v/r
Henry B. Davis IV
MAJ, FA
U.S. Army

? ? ?

Dear Major Davis,

I’m not sure of what you mean by “wheeled vehicle.” A Conestoga wagon? A railroad train? A bicycle? As far as I know the first wheeled, motorized vehicle to traverse the United States from west to east was a Winton driven by Horatio Jackson, leaving San Francisco on May 23, 1903, and reaching New York on July 26—thus winning a 50 dollar bet as to whether a motorcar could manage the feat in less than three months.

Sincerely,