Maps and Imagery

BenchMap: NGS Control Marker Locator for Android
Airway Maps on Internet Archive
PID Prefix Map
USGS Historical Topographic Map Explorer
This site catalogs historical USGS topo maps and makes them available as layers that you can easily toggle on and off. There is a transparency slider so you can easily compare historical maps with each other or with the current basemap. The map layers can also be downloaded.
USGS TopoView
TopoView provides a nice map interface to USGS’s Historical Topographic Map collection. Download GeoTIFFs, JPGs and KMLs at various scales for different uses.
USGS EarthExplorer
EarthExplorer offers aerial imagery that’s unavailable elsewhere—some of it dating back to the 1950s. Fill in your search criteria and then, on the data sets tab, select “aerial photo single frames” or “high resolution orthoimagery”. The Results tab will show the available images for your search.
PA Historic County Maps
PennDOT Transportation Maps, PDF format
PASDA: Pennsylvania Imagery Navigator
PASDA offers some tiles I haven’t found elsewhere, like LIDAR of the whole state, and black and white aerial imagery (à la TerraServer) from the 90s. These are great for locating old roads, trails and waterways. Note: as of July 2020, this website replaces Penn Pilot. It contains all the same imagery and more.
Penn Pilot: Historical Aerial Photographs of Pennsylvania
Historical USGS Topo Maps (Maptech/MyTopo)
Historical Topographic Maps (USGS: The National Map)
This page is somewhat confusing, but it offers good background information on the project. I prefer to use this search: US Topo and Historical Topographic Map Collection to go directly to historical topos, if I know the quad name.
MyTopo: Free Browsable USGS Topo Maps
NGS Historical Geodetic Control Diagrams
MapIndy: Historical Maps and Aerial Imagery of Indianapolis
Historical Map and Chart Collection, Office of Coast Survey
Geodetic Control Diagrams
Hate the new Google Maps? You’re not alone. Barry Hunter has created KMLMaps (formerly ClassyGMaps), which uses the Google Maps API to restore much of the old (and extremely useful!) functionality of previous iterations of Google Maps. Use the link above in your browser or grab the source code from GitHub.
PDF Quads: Free Printable USGS PDF Topo Maps
For those times when digital mapping and GIS overlays don’t cut it … National Geographic offers 7.5-minute topo quads in an easily printable format.
National Park Maps
These maps aren’t strictly related to survey mark hunting, and most don’t indicate any benchmark locations, but they’re an excellent resource for anyone hiking or hunting in our national parks.

Pretty Pictures

Flickr: USGS Geodetic Survey Markers
Not all are actually USGS markers, or geodetic markers; many different agencies and types are represented.
Recoveries Gallery (2019)
Zhanna’s recoveries from 2019—there are a few nice images here, if I may say so myself.

Airway Beacons & Arrows

Arrows Across America
More about the beacon and arrow system that guided our pioneer aviators.
Cibola County Historical Society Aviation Heritage Museum
Learn about the air history museum and restored beacon tower at Grants-Milan Airport in New Mexico.
Historical Map and Chart Collection, Office of Coast Survey
Aeronautical charts, among other types of maps, are available at this site.
Numidia Airport
Numidia Airport is the home of a lovingly restored tower beacon and caretaker’s shanty. The airport’s owner has provided a detailed history of the airport and the U. S. Airmail system.
Point of View, by Angela Minor
Hiding in plain sight, massive arrows—about fifty to seventy feet long and made of concrete—lie across the country, slowly succumbing to the ravages of time. First published in Oklahoma Today Magazine.
Strange Arrows Upon the Land, by Angela Minor
They’re oftentimes visible only from the sky. They point in seemingly random directions. They’re about 70 feet long and made of deeply sun-bleached concrete. What are they? First published in Blue Ridge Country Magazine.
Airport Lighting Brochures
These brochures from the 1920s and 1930s are provided by the Building Technology Heritage Library.
Maintenance of Airway Beacon Facilities, 1962 manual
Learn about the characteristics, operation and maintenance of airway beacon facilities, from the early acetylene-powered beacons to the familiar Crouse-Hinds DCB-36 beacons!
Beacon data files
Eastern US: Spreadsheet (.xlsx) | GPS Exchange (.gpx) | Google Earth (.kmz) | GeoJSON (.geojson)
Western US: Spreadsheet (.xlsx) | GPS Exchange (.gpx) | Google Earth (.kmz) | GeoJSON (.geojson)