How it works
How the map is built
Two public datasets, each good at half the question.
The structures: FCC Antenna Structure Registration
Anyone building a structure taller than 200 feet, or close enough to an airport to matter to pilots, has to register it with the FCC. The registry gives an exact location, height, structure type, owner and lighting requirement. We load the full weekly file and keep every structure that hasn't been dismantled. Some tower companies register their sites whatever the height, so plenty of structures here are shorter than 200 feet, and the file is not a complete list of short towers.
Heights in the registry are in meters; we show feet. The height is the overall height above ground, including whatever is mounted on top.
The registry names the owner, not the tenants. A tower registered to American Tower may carry Verizon, T-Mobile and AT&T, and the registry won't say so. The owner is whoever is on the registration, and registrations don't always follow a sale: some towers bought by the big tower companies still carry the name of the company that was acquired. About 750 structures here are registered under SpectraSite, which American Tower bought in 2005, many as "SpectraSite Communications, LLC. through American Towers, LLC." Those are American Tower sites.
The carriers: phones
OpenCelliD is a public database of cell signals reported by phones, with the network code that identifies the carrier and the radio technology (LTE, 5G NR and older). We match each reported cell to the nearest registered structure within 200 meters and list those carriers on that structure.
Cells with no registered structure nearby are grouped into approximate sites. Those are real cell sites, usually rooftops, small cells or short towers, but their pins are averages of phone reports and can be off by a few hundred meters.
- A carrier listed on a tower means phones saw that carrier's cell there. It is evidence, not a lease record.
- A carrier missing from a tower may just be unreported, especially in rural areas.
- 5G here means 5G NR was reported. It says nothing about which band or how fast.
What the map can't tell you
Which direction a tower's antennas point, how much capacity it has, or whether it is congested. Coverage depends on all of those as much as on distance.