410 Area Code: Maryland — Baltimore, Annapolis, and the Eastern Shore

Introduction

The 410 area code covers central and eastern Maryland — the Baltimore metro area and the entire Eastern Shore — and today shares that territory with two overlay codes, 443 and 667, under mandatory 10-digit dialing. It wasn't Maryland's original area code, though: the whole state carried a single code, 301, from 1947 until October 6, 1991, when the portion of Maryland from Baltimore eastward split off to become 410.

As cell phones and pagers ate through the new number pool faster than planners expected, regulators overlaid 443 onto the same footprint on July 1, 1997, then added a third overlay, 667, on March 24, 2012 — so every 410 number today shares its exact geography with two sibling codes, not one.

That combined geography is large: 410, 443, and 667 together cover roughly 18 Maryland counties, from Baltimore City and its immediate suburbs — Anne Arundel, Baltimore, Carroll, Harford, and Howard counties — across the Chesapeake Bay Bridge to every county on the Eastern Shore. Annapolis, the state capital, falls inside the same territory, as do Columbia, Towson, Bel Air, and Salisbury. A huge and economically varied stretch of Maryland shares one dialing identity even though it now takes three area codes to keep it supplied with numbers.

• Split from Maryland's original, statewide 301 area code on October 6, 1991
• Overlaid twice since — by 443 in 1997 and by 667 in 2012 — all three codes share identical territory
• Covers Baltimore, Annapolis, and all nine Eastern Shore counties under mandatory 10-digit dialing

Baltimore's harbor carries history well beyond its modern shipping numbers. During a 25-hour British naval bombardment of Fort McHenry on September 13–14, 1814, attorney Francis Scott Key watched from a ship in the harbor and, seeing the American flag still flying over the fort at dawn, wrote the poem that became "The Star-Spangled Banner" — later adopted as the U.S. national anthem in 1931. Fort McHenry still stands at the mouth of Baltimore's harbor today, inside the same 410 footprint as the modern port and biotech corridor that grew up around it.

Where the 410 Area Code Is Located

The 410 area code covers Maryland's most populous and economically active regions along with its entire Eastern Shore. Baltimore — Maryland's largest city and a major US port — sits at the core of the coverage area, surrounded by suburban counties including Anne Arundel, Baltimore, Carroll, Harford, and Howard. Annapolis, the state capital, falls within 410 coverage, as do major suburban communities including Columbia, Glen Burnie, Towson, and Bel Air.

East across the Chesapeake Bay Bridge, the coverage extends through all nine Eastern Shore counties — Cecil, Kent, Queen Anne's, Caroline, Talbot, Dorchester, Wicomico, Worcester, and Somerset — reaching towns like Elkton, Centreville, Easton, and Salisbury. Two other codes share this exact same footprint rather than serving separate ground: 443, overlaid in 1997, and 667, overlaid in 2012. A geographically distinct region — Maryland's western and central counties, including the DC suburbs — is served instead by 301/240. Calls between 410, 443, and 667 numbers anywhere in the shared territory are always local calls, never long-distance.

The Eastern Shore runs on a different economy than Baltimore and Annapolis: the Chesapeake Bay's blue crab and oyster fisheries. Commercial crabbing has shaped the region since companies began canning crabmeat there in 1878, and today Maryland's seafood industry brings in roughly $600 million a year, with the Bay's heaviest crab concentrations found in Eastern Shore tributaries like Eastern Bay. That seafood economy, alongside poultry processing and agriculture further inland, gives Eastern Shore towns like Easton and Salisbury a business character distinct from the government and healthcare economy on the western side of the Bay Bridge — even though every one of them shares the same 410/443/667 dialing footprint.

Johns Hopkins University and Johns Hopkins Hospital anchor the 410 economy more than any other single institution. Founded in 1876 as the nation's first research university, Johns Hopkins has led every U.S. university in annual federal research funding for more than four consecutive decades, and it is the largest private employer in both Baltimore and Maryland statewide. That research base supports a dense biotech and healthcare corridor stretching from East Baltimore's medical campus through the city and into the surrounding counties, alongside Under Armour's global headquarters at Baltimore's Locust Point and the Port of Baltimore, one of the busiest auto-import and roll-on/roll-off cargo ports on the East Coast. The 443 guide covers the neighbouring ground.

Phone Number Format and Dialing

Phone numbers in the 410 area code follow the NANP 10-digit format: (410) XXX-XXXX. For all calls within the 410/443/667 overlay region, dial the full 10 digits — even calling next door requires the area code. For US long-distance calls from outside Maryland, dial 1 + 410 + XXX + XXXX. For international callers, the format is +1 410 XXX XXXX. Mandatory 10-digit dialing has applied since November 1, 1991, just weeks after 410 itself went into service, so the region has never actually used 7-digit local dialing under the 410 code. The 410 region operates on Eastern Time (ET). More detail sits on our cloud business phone system page.

Benefits of a 410 Area Code Number for Businesses

A 410 area code number gives Maryland businesses a recognizable local identity with customers across the Baltimore metro and Eastern Shore. Research on call answer rates consistently shows that local numbers outperform toll-free and out-of-area codes. Beyond answer rates, a 410 number enhances local SEO — search engines factor phone number geography into local pack rankings, improving visibility in regional searches. A cloud business phone system makes it simple to claim a 410 number and route calls to a distributed team without opening a physical office in Maryland.

That local identity carries extra weight in a city that helped reshape its own industry. Oriole Park at Camden Yards, which opened downtown on April 6, 1992, is widely credited as the first "retro" major-league ballpark — a design that combined old-fashioned brick-and-steel styling with modern amenities, and one so successful that it kicked off a wave of similar downtown ballparks across the country over the following two decades. The Baltimore Ravens play a few blocks away, and both franchises anchor a sports and hospitality economy that businesses across the 410 footprint, from downtown hotels to Eastern Shore tourism operators, plan their calendars around.

> [TIP] Note: Get a local 410 Maryland number for your business — letsdial lets you go live in minutes, free number porting, no lock-in.

How to Get a 410 Area Code Phone Number

Obtaining a 410 area code number is straightforward through several routes. National carriers including Verizon, AT&T, and T-Mobile offer 410 numbers as part of their Maryland service plans. For a business line, remote team number, or virtual Maryland presence, VoIP providers offer the fastest activation: sign up with a provider like letsdial, select an available 410 number, configure call routing, and go live within minutes.

Number portability means you can also transfer an existing 410 number to a new provider without changing the digits. letsdial supports free porting in both directions: your 410 number transfers in at no cost, and it ports out freely if you ever switch.

Annapolis, the state capital inside the 410 footprint, is home to the United States Naval Academy, established on October 10, 1845 at the old Fort Severn Army post with just 50 midshipmen and seven professors. The academy has grown to roughly 4,400 midshipmen today across a 338-acre campus, and it remains one of the region's most recognizable institutions — a steady source of government, defense-contractor, and maritime business calling into the Annapolis area that a locally recognized 410 or 443 number is well positioned to reach.

Scams and Safety for 410 Area Code Users

Caller ID spoofing allows scammers to display any local 410 number while calling from anywhere in the world. Common scams targeting the 410 region include phishing calls impersonating Johns Hopkins Health System or the University of Maryland Medical System, robocalls promoting fake debt consolidation, and spoofed calls appearing to come from state government agencies. Register at donotcall.gov and report suspicious calls to the FTC at reportfraud.ftc.gov.

Businesses face the flip side of that same trust problem. An unsigned outbound call from a legitimate 410 number can still land as "Spam Risk" on a recipient's phone if it isn't authenticated under STIR/SHAKEN, the industry framework carriers use to verify that a caller ID hasn't been spoofed. A cloud provider that applies A-level attestation automatically, and files the required 10DLC registration for business text messaging, keeps a legitimate Maryland business from being mistaken for the same scammers it's trying to be distinguished from. That record is published in full as public record for area code 410.

Conclusion

The 410 area code has anchored Maryland's Baltimore-to-Eastern-Shore corridor since it split off the state's original, statewide 301 code in 1991, and two later overlays — 443 and 667 — now share that same territory rather than serving new ground. Whether you're identifying an unfamiliar caller, building a local presence for a Maryland business, or simply making sense of why every call needs 10 digits, understanding how these three codes overlap gives you what you need to communicate confidently across the region.

Frequently Asked Questions