Warren is a city in Macomb County in the U.S. state of Michigan. The city is home to a wide variety of businesses, including General Motors Technical Center, the United States Army Detroit Arsenal, home of the Tank-Automotive and Armaments Command (TACOM) and the Tank Automotive Research, Development and Engineering Center (TARDEC), they are now creating larger facilities, including an eight story building, the National Automotive Center (NAC), and the headquarters of Big Boy Restaurants International, Campbell Ewald, and Asset Acceptance. There are nine recognized Michigan historical markers in the city. They are: John Theisen House; General Motors Technical Center; Village of Warren; Governor Alexander Joseph Groesbeck; Warren Township District No. 4 School; Warren Union Cemetery; Erin - Warren Fractional District No. 2 School; Detroit Memorial Park Cemetery; and finally Detroit Arsenal Tank Plant