Some new, simple and extremely fast bounding procedures are presented for large-scale instances of the Simple Plant Location Problem. The lower-bounding procedures are based on dual ascent. The fastest of them runs in O(mn log m) time, where m and n are the number of locations and clients, respectively. The upper-bounding procedures are based on iteratively dropping facilities, and the fastest of them runs in O(m(n + log m)) time. Extensive computational results show that, in practice, the procedures give very good bounds extremely quickly.