I've no idea how much of this is correct, but here's what Wikipedia has to say on that subject:
Manteca is a city in the Central Valley of California, 76 miles east of San Francisco. It was founded in 1861 by Joshua Cowell. Cowell claimed around 1,000 acres and built houses on what is now the corner of Main and Yosemite where Bank of America now stands.
In 1873, the Central Pacific Railroad laid track directly through the area. The residents wanted to refer to their new train station as "Cowell Station", but there was already a Cowell Station near Tracy. So, the residents agreed to change the name of the community, choosing "Monteca" as the new name. This was misprinted as "Manteca" (Spanish for lard) by the railroad, and the misspelled version was eventually accepted as the name of the town.
Hence in 1918, Manteca was incorporated as a city and Joshua Cowell became its first mayor.
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