Three hundred and forty-four tick samples were collected from vegetation at Taksin Maharat National Park, Tak province, northwestern Thailand. They were morphologically identified and molecularly confirmed by 16S rRNA andCOIgenes asDermacentor laothaiensis(n = 105),D. steini(n = 139), andD. auratus(n = 100). These ticks were examined for the spotted fever group rickettsiae (SFGRs) using PCR and DNA sequencing of six genes; 17-kDa,gltA, 16S rRNA,ompA,ompB, andsca4. Of these ticks, 6.10% (21/344) gave positive results for the presence of SFGRs. Phylogenetic analyses of the SFGRs clearly indicated that a novel genotype assigned asCandidatusRickettsia takensis was detected inD. laothaiensis(19/105) and at lesser frequency inD. steini(1/139). Furthermore,CandidatusRickettsia laoensis was also found at a low frequency inD. auratus(1/100), the first record in Thailand. Although, the pathogenicities of these SFGRs remain unknown, our findings suggest potential risks of SFGRs being transmitted via ticks near the border between Thailand and Myanmar, a gateway of daily migrations of local people and visitors both legal and illegal.