The industrial era was well underway by the beginning of the twentieth century. In 1906, the Trumbull Steel facility (later Republic Steel, then WCI Steel) became the first integrated steelworks built in Trumbull County. Immigration increased as a result of this new industry, and the surrounding farmland was subdivided into thriving residential neighborhoods. Between 1910 and 1920, population increased by 144 percent, giving Warren the distinction of being the fastest growing town in Ohio during that decade.
By the mid-1920s, industrial and business expansion had swept the county. Additional steelworks were established, and the wealthy Perkins and Packard families donated land that has become the backbone of Warren's picturesque riverside park system. The skyline of downtown Warren reached its present outline in 1923 and has not since changed; the city has the distinction amongst major Ohio cities of having the only downtown skyline still standing in the shadow of the spire of a grand nineteenth century church.
After the Second World War, the region witnessed the growth of Packard Electric and other local divisions of national corporations, including the General Motors Lordstown Assembly Complex. Local civic leadership was devoted to keeping up with the burgeoning demand for social, educational, and cultural facilities. In the 1970s, the collapse of the steel industry caused economic distress on regional and national levels for nearly two decades.
Today, the City of Warren and Trumbull County have diversified their interests in the manufacturing industry, are more closely in-step with national employment trends, and look confidently toward promoting growth and development in the twenty-first century.