 Major employers outside of Austin include Dell (Round Rock), MD/Totco in Cedar Park (a division of National Oilwell Varco), Southwestern University in Georgetown, and Texas State University in San Marcos.The principal highways in the metropolitan area are Interstate 35 and the MoPac Expressway (State Highway Loop 1), both of which are the primary North/South roadways.Other important arteries in the city and its immediate vicinity are U.S. Highway 183 (also known as "Research Blvd.