A Gram-positive, endospore-forming, new Bacillus species, strain BL4-$6^T$, was isolated from tidal flat sediment of the Yellow Sea. Strain BL4-$6^T$ is a straight rod, with motility by peritrichate flagella. The cell wall contains meso-diaminopimelic acid, and the major respiratory quinone is menaquinone-7. The major fatty acids are iso-$C_{15:0}$ and summed feature 3 (containing $C_{16:1};{omega}7c/;iso-C_{15:0}$ 2OH, and/or iso-$C_{15:0};2OH/C_{16:1};{omega}7c$). Cells are catalase-positive and oxidase-negative. The G+C content of the genomic DNA is 38.0 mol%. Based on a comparative 16S rRNA gene sequence analysis, the isolate belongs to the genus Bacillus, forms a clade with the Bacillus cereus group, and is closely related to Bacillus mycoides (98.5%), Bacillus cereus (98.5%), Bacillus anthracis (98.4%), Bacillus thuringiensis (98.4%), Bacillus weihenstephanensis (98.1%), and Bacillus pseudomycoides (97.5%). The isolate showed less than 85% similarity of the gyrA gene sequence and below 95% similarity of the rpoB gene sequence to the members of this group. DNA-DNA relatedness between strain BL4-$6^T$ and B. cereus group was found to be in a range of 22.8-42.3%, and thus BL4-$6^T$ represents a unique species. On the basis of these studies, strain BL4-$6^T$ (=KCTC $13319^T$ =JCM $15802^T$) is proposed to represent the type strain of a novel species, Bacillus manliponensis sp. nov.