CELAYA, Mexico -- In opening its $800 million assembly plant here to build the 2015 Fit subcompact hatchback and crossover variant, Honda is joining a rapidly growing slate of automakers and suppliers in the central Mexican state of Guanajuato.

The Celaya plant will build about 200,000 units annually, and will boost Honda's annual North American production capacity to 1.92 million units -- representing 95 of all Honda and Acura vehicles now sold in North America.

The Honda Fit assembly plant will be mated to a $470 million continuously variable transmission plant, which will open in late 2015 on the same grounds, with initial capacity of 350,000 units, rising to 700,000 at its peak.

"Having a new overseas factory, with a new vehicle, and a new transmission factory, this is something we haven't done before, and this is a new challenge for us," Honda CEO Takanobu Ito said in a media roundtable. "The challenge is to make this into a highly profitable business."