In anticipation of the developments, the entire area (947 acres; 383 ha) was annexed by the city of Tukwila in November 1957. Southcenter Corporation strategically purchased  at what would eventually become the intersection of two major freeways, the Seattle-Tacoma Freeway (I-5) and I-405. The construction schedule of the mall was dependent on the construction of the freeways.
The area (947 acres; 383 ha) was annexed by the city of Tukwila in anticipation of developments, and Southcenter Corporation strategically purchased land at a location that would become the intersection of two major freeways, the Seattle-Tacoma Freeway (I-5) and I-405. The construction schedule for the mall depended on the completion of the freeways.