The efficient location recognition of multiple outage lines is critical to not only cascading failure elimination but also repair cost reduction. Most of existing methods, however, fail to handle location recognition well. This failure typically occurs because the methods cannot overcome three challenges: the very limited number of Phasor Measurement Units (PMUs), the high computational complexity, and the possibility of concurrent multiple outage lines. This paper presents an efficient algorithm inspired by the ambiguity group theory to recognize the most likely outage line locations with limited PMUs. Using IEEE 14-, 57-, and 118-bus system, the experimental study demonstrates that the proposed technique can successfully recognize the most likely multiple outage line locations with a reasonable computation complexity. © 2014 IEEE.