Spam calls from area code 240? Here's how to stop them.
Area code 240 is one of several stacked over Rockville, MD — and the spammers dialing you from it aren't there at all. Here's why, and how to shut it down free.
If your phone keeps lighting up with area code 240 calls, here's the truth: it's almost certainly not someone in Rockville, MD. It's a robocaller spoofing a western Maryland number so the call looks local and you pick up. You hang up, they dial the next 240 number. You're one row in a spreadsheet.
Don't block 240 — screen it. Real calls come from 240 too. Known callers should ring through; unknown 240 numbers should hit a wall first.
What 240 actually is
Across a sample of 18,440 recent FTC reports (through 2026-07-23), consumers logged 51 complaints about calls that displayed a 240 number. Because caller ID is spoofed, almost none actually originated in Rockville — the number is a costume, and this is how often it gets worn against people who share it.
240 is a newer code. Its middle digit (4) was impossible before 1995 — back then the middle digit was locked to 0 or 1. When those ran out, the plan opened up 2–9, and codes like 240 were minted, almost always as overlays stacked on an older code in the same place. Newer overlay codes are prime spoofing material because they still look local but nobody has them memorized.
Around Rockville, 240 shares the dialing area with 301. When multiple codes overlay one region, every call is ten digits and a spoofing engine gets a much deeper pool of local-looking numbers to fake — so overlaid metros like this one see heavy neighbor spoofing.
One tell the spoof can't hide: time. Numbers on 240 belong to the Eastern time zone. A "local" 240 call that rings at 3 a.m. almost always originated in a boiler room several zones away, dialing your daytime from their own.
Why 240 keeps calling you
Spoofing engines pull the first six digits of your number and dial matching 240 numbers — the “neighbor” trick. A call sharing your area code and prefix feels safe, so answer rates jump. That's the whole scam: familiarity. Read the mechanics in neighbor spoofing, and why you got picked in why me?
Shut down 240 spam calls — free
- Silence unknown callers. The single biggest win. Set it up on iPhone or Android in 30 seconds.
- Turn on your carrier's filter. Free on AT&T, Verizon, and T-Mobile.
- Register on the Do Not Call list. Won't stop scammers, but it makes the legal ones back off and gives you standing to report.
- Weaponize the rest. The calls that still get through? Hand them to the Crew — an AI answers in character and wastes the scammer's time on a call they thought was a real mark.
Why am I getting spam calls from area code 240?
Because auto-dialers spoof it. They fake a 240 (Rockville, MD) number so the call looks local and you answer. The caller is almost never actually in Rockville — the number is a mask, and a newer overlay like 240 picks it precisely because it looks close to you. See neighbor spoofing.
Is every 240 call spam?
No. 240 and its overlay siblings (301) carry plenty of real Rockville traffic. That's why blocking the whole code backfires. The fix is screening — let known callers through, send unknown 240 numbers to a screener.
How do I stop 240 spam calls for free?
Turn on Silence Unknown Callers (iPhone / Android), register on the Do Not Call list, and switch on your carrier's free spam filter. For the ones that still slip through, hand them to the Crew — the AI answers in character (in English, Spanish, Russian, or Mandarin) and wastes the scammer's time instead of yours.