All 6 Maryland Area Codes
Every active code: tap any card for its full guide, who called, cities and ZIPs, map, spam patterns and local time.
Got a call from a Maryland number you don’t recognize?Open that code’s guide above for its full prefix lookup. AT&T ActiveArmor® blocks spam automatically, included with AT&T wireless plans.
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Included with AT&T wireless plans. Requires compatible device/service and download of the AT&T ActiveArmor® app. Other terms & restrictions apply. May not detect all threats and may block wanted calls. Some features require Advanced mobile security ($7/mo.). See terms.
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Offer details
Service good for 30 days. Data: Limited to 100GB of data and 25GB of hotspot data. No additional data is available after limit is reached. Video is limited to SD quality. Talk & Text: Includes unlimited talk & text within the U.S. and unlimited text from the U.S. to over 230 countries. Limits: One trial per user. An unlocked, dual eSIM iPhone is required. You’ll receive a trial phone number that belongs to AT&T and is not available to be ported to another carrier or otherwise retained. Trial plan features and details may differ from or be unavailable in other AT&T plans. U.S. only. All terms subject to change at any time.
Why Metro Baltimore Has 6 Area Codes
When a region uses more numbers than one code can hold, new codes are overlaid on the same territory rather than forcing anyone to change numbers. Metro Baltimore now uses 227, 240, 301, 410, 443 and 667: same neighborhoods, ten-digit dialing, and every one of them covered by its own guide above.
Maryland Area Codes by City
The largest Maryland communities and the area codes that serve them. Every city links to its local AT&T internet page.
How Maryland Got Its Codes
Every Maryland area code, in the order it entered service. Splits carved new regions; added codes overlay existing ones, which is why ten-digit dialing is standard.
| In service | Code | How it arrived |
|---|---|---|
| 1947 | 301 | One of the original area codes of 1947 |
| 1991 | 410 | Added to the 301 region |
| 1997 | 240 | Added to the 301 region |
| 1997 | 443 | Added to the 410 region |
| 2012 | 667 | Added to the 443 region |
| 2023 | 227 | Added to the 301 region |
Source: NANPA NPA database, July 2026. Regenerated monthly.
Maryland Area Code Map
Every active Maryland area code at a glance, anchored to the metro each one serves. Tap any code above for its detailed coverage map.
Explore the interactive map
Click any region to open that area code's full guide. Hover for county names.
Open the printable Maryland area code map (PDF) - poster format with a QR code back to this page.
Internet, wireless & stores across the state
AT&T Home Internet in Maryland
AT&T home internet is available across Maryland, checked address by address; every area code guide above lists its cities and what’s offered there.
AT&T Fiber: Ltd. avail/areas. Speeds based on wired connection. Actual speeds vary. For 5-GIG, single device wired speed maximum 4.7Gbps. For more info., visit att.com/speed101.
Start with home internet in Maryland, or pair it with wireless in an internet + wireless bundle.
AT&T Wireless in Maryland
AT&T’s 5G network covers most of Maryland. ActiveArmor® spam blocking is included with every unlimited plan, your number stays yours when you move between Maryland codes, and great cell phone deals in Maryland are a tap away.
AT&T may temporarily slow data speeds if the network is busy. 5G req’s compatible plan & device. Coverage not available everywhere. Learn more at att.com/5Gforyou.
AT&T Stores Across Maryland
From the Baltimore metro to Hanover, Columbia and beyond, walk in for switching, porting, upgrades and hands-on help. Every area code guide lists its nearest stores.
Find stores in: Baltimore · Hanover · Columbia · Hagerstown · Bowie
