The Maacama Fault extends through the northern California Coast Ranges from around Ukiah northward toward Laytonville and beyond, in Mendocino County. It is a right-lateral strike-slip fault and the northern continuation of the Rodgers Creek–Hayward system, carrying plate-boundary motion parallel to the San Andreas Fault.
The fault is notable for its steady aseismic creep, which slowly bends curbs, walls and roadways in the town of Willits and offsets features along its trace. This continuous slip releases some strain gradually while other locked sections store energy.
No great historical earthquake has been assigned to the Maacama Fault, but its high slip rate and paleoseismic record indicate it is capable of a major rupture. It is regarded as one of the more significant seismic hazards of the sparsely populated northern Coast Ranges.