Reggie Smithers wrote:

It appears that Cortez is an Americanized spelling of the Sea of Cortes.
They have changed the s to a z to reflect the phonetic spelling of Cortes.

If you run a Goggle on Mar de Cortés you will get 1.9 million hits, so
it appears the Mexicans do spell it Cortes.

And I've found that most folks who proffer 'Cortes' or Gulf of
California have never been to the area. Boaters, fisherman, and divers
with decades of travels there refer to it simply as the Cortez.

--
Skipper