November 12, 1921: "B.H. Mace, deputy supervisor of the California National Forest, has returned from Hammerhorn mountain where he has been supervising the erection of a house for the forest service fire lookout stationed at that point." (Mariposa Gazette)
July 9, 1930: "C.M. Bucknell left this week for the lookout station on Hammerhorn, where he will pass the summer in the forest service." (Ukiah Republican Press)
December 3, 1930: "Construction of 1200-gallon water tank at Hammerhorn Lookout." (Ukiah Republican Press)
April 15, 1932: "Forest service for the summer has been announced by District Ranger F.O. Long. Appointees will go on duty June 1. Stations are as follows: C.M. Bucknell, Hammerhorn lookout." (Ukiah Dispatch Democrat)
September 25, 1946: "Mendocino National Forest and C. Henry, Assistant Dispatcher from Alder Springs, and R. Bangsberg from Covelo made the patrol flight September 15. During this flight they dropped mail to Hammerhorn Lookout, but because of strong winds and necessary high flying speed, Mrs. Williams at the lookout, had some difficulty locating the parcels, which came down in rough country about one-quarter mile from the lookout." (Ukiah Republican Press)
National Geodetic Survey
DESIGNATION - HAMMERHORN LOOKOUT TOWER PID - LU2031 STATE/COUNTY- CA/TRINITY COUNTRY - US USGS QUAD -
DESCRIBED BY COAST AND GEODETIC SURVEY 1942 (JCS) THIS UNOCCUPIED INTERSECTION STATION IS LOCATED IN THE MENDOCINO NATIONAL FOREST, AND IN THE MIDDLE EEL PRIMITIVE AREA. IT IS NEAR THE MENDOCINO-TEHAMA COUNTY LINE AND IS APPROXIMATELY 22 MILES NE OF COVELO, CALIFORNIA. IT IS A PERMANENT LOOKOUT STATION ON THE SUMMIT OF HAMMERHORN MOUNTAIN. THE CENTER OF THE STRUCTURE WAS CUT IN AS AN INTERSECTION STATION.