I see in the biography of Hylan Benton Lyon that he is shown as having been assigned to Fort Huyma, California as his second assignment after graduating from West Point. This biography seems to have been paraphrased from his biography in Battle, Perrin & Kniffin, Kentucky - A History of the State (1885), which makes the same statement.
I can find no reference to a Ft. Huyma, in California or elsewhere. There was though a Ft. Yuma in the Southern California desert, established in 1851. Doesn't it seem likely that's where he was stationed?
A simple search shows that General Lyon was indeed assigned to Ft. Yuma when he was a lieutenant in the U.S. Army.
Actually, it doesn't. That's yet another paraphrasing of the same book, but in this case the person who posted it came to the same conclusion I did, that "Huyma" was probably a mis-spelling of "Yuma." There is no new information in that article, except what I added this morning about Lyon's third wife.
I don't know what: "New" information you're expecting to find. Your question was: "Doesn't it seem likely that's where he was stationed?" (Meaning Ft. Yuma).
The answer to your question is: "Yes, it does." Perhaps I should have limited my answer to that. At any rate, there are various sources that make the same conclusion. Here is a collection of his papers along with a bio that says that he was stationed there.