The efficient location identification of multiple line outages is critical to not only cascading failure elimination but also repair cost reduction. Most of existing methods, however, fail to handle location identification well. This failure typically occurs because the methods cannot overcome two challenges: the very limited number of phasor measurement units (PMUs) and the high computational complexity. This paper presents an efficient algorithm inspired by the ambiguity group theory to identify the locations of line outages with limited PMUs. Using 14-, 57-, 118-, 300-, and 2383-bus systems, our experimental study demonstrates that the proposed technique successfully identifies the most likely multiple line outages while attaining a 500 × speedup when compared to the method of exhaustive search.