Interstate 39 (I-39) is a major highway in the United States that runs through the states of Illinois and Wisconsin. It stretches approximately 180 miles, connecting Interstate 90 and Interstate 94 in the north to Interstate 55 in the south. The highway serves as an important route for both local and long-distance travel. I-39 was established in the 1990s and is part of the larger Interstate Highway System. It passes through several cities, including Rockford and Madison, providing access to various attractions and services. The highway is designed to facilitate efficient transportation and support economic activities in the regions it traverses.