Texas State Highway 121 is a major highway located in the state of Texas. It runs approximately 80 miles, connecting the cities of Lewisville and McKinney. The highway serves as an important route for commuters and travelers in the rapidly growing areas of Collin County and Denton County. Originally designated as a farm-to-market road, Highway 121 has been expanded and upgraded over the years. It features multiple lanes and interchanges, facilitating access to various local attractions, shopping centers, and residential neighborhoods. The highway plays a crucial role in the regional transportation network.