Mount Thayer

{{Short description|Mountain in California, US}}

{{Use mdy dates|date=January 2025}}

{{Infobox mountain

| name = Mount Thayer

| photo = Mount Thayer from Mount Umunhum April 2022 3 (cropped).jpg

| photo_caption = Mount Thayer seen from Mount Umunhum

| elevation_ft = 3502

| elevation_ref = {{NAVD88}}{{cite ngs|HS4915|Thayer 2 reset}}

| prominence = 303 ft (92 m)

| location = Santa Clara County, California, U.S.

| range = Santa Cruz Mountains

| map = California

| map_caption = Location in California

| map_size = 200

| coordinates = {{coord|37.163855539|N|121.918707136|W|type:mountain_region:US-CA_scale:100000_source:ngs|format=dms|display=inline,title}}

| range_coordinates =

| coordinates_ref =

| topo = USGS Los Gatos

| type =

| age =

| last_eruption =

| first_ascent =

| easiest_route = Mt. Umunhum Road

}}

Mount Thayer is a mountain in the Santa Cruz mountain range located in Santa Clara County, California. The summit is in a section of the abandoned Almaden Air Force Station, 1.5 miles northwest of Mount Umunhum. The elevation of the summit is at {{convert|3502|ft|0}} feet. An old derelict building, surrounded by telephone poles, is located on the summit. Mount Thayer, along with the surrounding property, is off limits to the public.

{{cite news

| url = http://www.openspace.org/preserves/maps/pr_sierra_azul.pdf

| title = Sierra Azul Open Space Preserve — map showing restricted access areas

| work = Midpeninsula Regional Open Space District

| publisher = Midpeninsula Regional Open Space District

| accessdate = 2009-08-16 }}