Rolla (rŏl´ə), city (1990 pop. 14,090), seat of Phelps co., S central Mo.; inc. 1861. It is a regional center for a livestock and farming area of the Ozarks. Apparel, roof and floor trusses, chemicals, cabinets, and limestone are manufactured and there are wineries nearby. The Univ. of Missouri has a campus in the city, and the U.S. Geological Survey Mid-Continent Mapping Center and the headquarters of the Mark Twain National Forest are also there. Caves and springs abound in the area.