Downtown is the largest central business district in the city of Houston and the largest in the state of Texas, located near the geographic center of the metropolitan area at the confluence of Interstate 10, Interstate 45, and Interstate 69. The 1.84-square-mile (4.8 km²) district, enclosed by the aforementioned highways, contains the original townsite of Houston at the confluence of Buffalo Bayou and White Oak Bayou, a point known as Allen's Landing. Downtown has been the city's preeminent commercial district since its founding in 1836.