In 2011,Ehrlichia muris eauclairensis(EME) was described as a human pathogen spread by the blacklegged tick,Ixodes scapularis. Until very recently, its reported distribution was limited to the upper midwestern United States, mainly in Minnesota and Wisconsin. In this study, we report the detection of EME DNA in 4 of 16,146 human bitingI. scapularisticks submitted from Massachusetts to a passive tick surveillance program. Active tick surveillance yielded evidence of EME local transmission in the northeastern United States through detection of EME DNA in 2 of 461 host-seekingI. scapularisnymphs, and in 2 white-footed mice (Peromyscus leucopus) of 491 rodent samples collected in the National Ecological Observatory Network (NEON) Harvard Forest site in Massachusetts.