In the literature of the California deserts, the word "Mojave" is spelled with both the "j" and the "h." This is another of those things where no particular approach is the correct one. The important thing is to pick a convention and stick with it. In the Mojave Road Guide the spelling "Mojave" is used for everything on the California side of the Colorado River. The county by that name in Arizona is officially spelled "Mohave" so if any reference to it was made, the "h" would be used, but otherwise the "j" is used except in direct quotations. In quotations the form chosen by the original writer is preserved.
Extract from Dennis G. Casebier's , "Mojave Road Guide", Tales of the Mojave Road Number 11, June 1986.