Complex sentence: The district's traditional boundaries were Western Avenue on the west, Washington Boulevard on the north, Main Street on the east, and Exposition Boulevard on the south; however, the Santa Monica and Harbor freeways now form its northern and eastern boundaries, respectively.
Split into simpler sentences: The district's traditional boundaries are Western Avenue on the west, Washington Boulevard on the north, Main Street on the east, and Exposition Boulevard on the south. However, the Santa Monica and Harbor freeways are often considered to be its northern and eastern boundaries, respectively.