A 1900 Lohner? But that had electric hub. Spyker made the first mechanical 4x4 in 1902
Or do you mean "off roader" - that would be the Willis Overland or American Bantam - the 2 cars entered for the original military trial and later by the Ford Pygmy
The Willis went into production as the MA / MB - that is what you are thinking via the CJ. But its a different vehicle by a long chalk to a Wrangler. S1 & early S2 Landies are closer to the MB than a Wrangler is.
And interesting enough Ford where the first to use the GP tag. The Pygmy went into production as the Ford GPW -- G for Gov and P their standard identifier for that wheelbase.
And then there is the Mitsubishi PX33 (prototype only 1933), Volkswagen Kubelwagen and GAZ-64 (early 1941) and GAZ-61 (1938)