Harvey Mountain Lookout on the Lassen National Forest is the only known remaining example of the original 1918 design of a 4A lookout cab with thick iron straps covering the wood supports between the windows. Built in 1919 it may be the longest serving active lookout in California. In 1934 a steel Aermotor fire tower was constructed next to the lookout with the cab used as quarters. It was later removed and fire detection moved back to the ground cabin.