Louisiana Area Codes by Region

Area Codes Serving Louisiana

Five regions divide Louisiana's numbering, and one of those regions now carries two codes. The working set is 225, 318, 337, 457, 504 and 985. The oldest of the group is 504, which today sits over the New Orleans core. Baton Rouge and the capital parishes answer to 225. Acadiana and the southwest belong to 337. Southeast Louisiana outside the New Orleans core runs on 985, wrapping the Northshore and the bayou parishes. North and central Louisiana is 318 territory, with 457 layered over the exact same ground. None of this layout is arbitrary. Each code was carved out at the point the previous one ran short of numbers.

Two of those codes share one map. 318 and 457 cover identical territory, which is what an overlay means once you get past the jargon. The other four keep their own borders and do not overlap. Wireless numbers blur the picture a little, since a phone holds onto its code no matter where its owner moves. Someone living in Ruston can easily carry a 504 number from an old address in Metairie. Judging a caller by the area code alone will steer you wrong fairly often.

Louisiana Area Code Coverage by Parish

Parish lines and numbering lines mostly agree across Louisiana, though not perfectly. Telephone geography was drawn around switching equipment and rate centers rather than around parish boundaries, so a handful of edges land in odd places. For the everyday job of matching a town to a code, the broad picture holds up well.

• Baton Rouge, Zachary, Gonzales, Plaquemine and the capital parishes - 225
• Shreveport, Bossier City, Monroe, Ruston, Alexandria and Natchitoches - 318 and 457
• Lafayette, Lake Charles, New Iberia, Opelousas, Crowley and Leesville - 337
• New Orleans, Chalmette, Metairie and most of Jefferson Parish - 504
• Slidell, Covington, Hammond, Houma and Thibodaux - 985
• Lower Plaquemines communities near the river's end - 504, after a move back from 985

A parish sitting on a boundary can hold numbers from either side. When the exact code matters, the number in hand settles it faster than the parish name does.

Note: Parish government offices sometimes publish numbers in more than one area code when the parish straddles a numbering boundary.

Louisiana's First Area Code Overlay

Until 2025, every new code in Louisiana arrived by splitting an old one. 457 broke that pattern. NANPA documented the plan in Planning Letter 617 back in June 2023, and the Louisiana Public Service Commission announced the rollout on February 18, 2025. Nobody in the 318 region had to give up a number. What changed was the dialing. Permissive 10-digit dialing opened on February 24, 2025, so seven-digit local calls kept going through for six more months. That grace period closed on August 25, 2025. New 457 numbers started going out on September 25, 2025. The commission stated plainly that prices, coverage, local calling areas, rates and services all stayed put, and that access to N11 codes was untouched.

State agencies got their own warning well ahead of the cutover. The Louisiana Office of Technology Services issued technology notice TIN 25-02 on January 24, 2025, telling agencies that seven-digit local calls in the 318 region would stop completing after the August deadline.

A notice like that one is why the change landed so quietly. Agencies had time to reprogram speed dials, alarm panels and fax machines before the deadline instead of scrambling after it.

Two other Louisiana codes were already dialing 10 digits, for a completely unrelated reason. Both 337 and 504 had live 988 exchanges when the national crisis line launched, so both moved to 10-digit local dialing on October 24, 2021. No overlay was involved anywhere in that change. That leaves 225 and 985, where no statewide order requires 10 digits, so what your line accepts comes down to your carrier and your local calling rules. The FCC ten-digit dialing guide explains why the 988 rollout forced the switch in the first place. Service codes, star codes and the rest of the dialing rules are laid out on the Louisiana phone codes page.

Louisiana Area Code Splits and Overlays

Two mechanisms shaped the map, and they feel very different to the people living under them. A split hands part of an old code's territory to a new code, so a share of customers wake up with a different number on their business cards. Louisiana went through three of those. 225 came out of 504 in 1998, 337 came out of 318 in 1999, and 985 came out of 504 in 2001. An overlay does the opposite. It stacks a second code onto the same ground and leaves every existing number alone, in exchange for a longer dial string that everybody has to learn.

NPA

Numbering plan area, better known as the area code. It is the first three digits of a 10-digit number.

NXX

The central office code, or prefix. These are the next three digits, and they point at a rate center rather than a region.

Split

A new code takes over part of an old code's map. Customers in the transferred area get a new area code.

Overlay

A new code is added on top of the same map. Existing numbers stay exactly as they are, and every local call needs 10 digits.

Permissive dialing

The transition window when both the old and new dialing patterns still connect. It ends on a fixed date set by the regulator.

Splits produce a clean map: one code, one region. Overlays trade that clarity for a longer dial string, which is why regulators now lean toward them.

Louisiana Area Code Timeline

Go back to 1947 and the whole state fits under one code. 504 covered every parish when the North American Numbering Plan first drew its lines. Ten years later Louisiana had outgrown that arrangement, and 318 took everything west of the Mississippi River. The next four decades were quiet. Then came a run of splits in the late 1990s and early 2000s, driven by fax lines, pagers, second lines and the first wave of cell phones eating through the supply of numbers. The most recent entries have nothing to do with new territory and everything to do with how many digits a caller has to press.

Read down that column and the Louisiana pattern is easy to spot. Splits cluster in the growth years. Dialing changes cluster in the last five.

Katrina and the 985 Area Code

Storms rarely redraw a phone map. One did. When 985 was created in 2001, it picked up communities down the lower end of Plaquemines Parish. Hurricane Katrina then wrecked switching facilities along that stretch, and service for those communities ended up running through New Orleans equipment instead. The numbering followed the wiring. Those communities went back to 504, with permissive dialing in 2007 and a mandatory switch in 2008. It is a small footnote in Louisiana numbering history and an unusually literal one. The area code moved because the switch serving the phones moved.

Note: Older listings for lower Plaquemines addresses may still show 985 numbers, so confirm the current listing before dialing an old contact.

Prefixes Inside Louisiana Area Codes

Behind each area code sits a second layer of three digits. In state directory assistance at 225-342-6600, the 342 is the prefix, also called the central office code. Blocks of those get handed to carriers for specific rate centers, and over decades they settle into recognizable patterns. Louisiana state offices lean heavily on 225-219 for technical support lines. GOHSEP, the Department of Public Safety and the Baton Rouge motor vehicle office cluster under 225-925. City-parish government in Baton Rouge uses 225-389, and the LSU campus there runs on 225-578. The Louisiana Supreme Court clerk record sits under 504-310.

NANPA publishes the underlying assignments in its Central Office Code Assignment Records, downloadable by state and sorted by area code and prefix.

Those files are the authoritative answer when a prefix looks unfamiliar. They also show how thin the remaining supply gets inside a busy area code, which is the arithmetic sitting behind every overlay decision.

A prefix hints at where a number started life, not where it lives now. Portability lets a customer carry a number to another carrier, and a block first issued to landlines can end up serving mobile or VoIP accounts. For the practical routes to identifying who holds a number today, the Louisiana phone number lookup options cover more ground.

How New Louisiana Area Codes Arrive

Adding a code is slow and heavily documented. NANPA tracks how fast prefixes are being consumed inside each area code and projects the date the supply runs out. As that date approaches, a relief planning process opens and a planning letter lays out the choices: split the region, or overlay it. The state regulator makes the call. For 318 that decision belonged to the Louisiana Public Service Commission, which chose the overlay and published the schedule in its 318 and 457 press release.

1. NANPA forecasts that an area code will exhaust its supply of prefixes.
2. A relief planning letter documents the options and the recommended plan.
3. The state commission approves either a split or an overlay.
4. Carriers implement, a permissive dialing window opens, and a mandatory date closes it.

Every one of those steps leaves a paper trail in NANPA's relief planning letters.

The Louisiana entry is Planning Letter 617, which carries the 457 overlay detail. Reading the letter is the quickest way to confirm whether a rumor about a new code has anything behind it.

Nothing further is queued up for Louisiana right now. The 457 overlay was the relief 318 needed, and no additional Louisiana relief code appears in official sources. If one is ever proposed, residents would not have to do a thing. Overlays only add new numbers to the pool. The one already printed on your bill keeps working.

Note: A relief plan can be announced years before any dialing changes, so the planning letter date and the cutover date are rarely close together.

Verifying a Louisiana Area Code

Scam calls have made people wary of unfamiliar codes, and 457 is new enough that some Louisiana residents treat it as out-of-state. It is not. A quick check settles the question either way. NANPA's area code reports list every code in service, the state it belongs to, and when it went live. The FCC covers the dialing rules that apply once you know a code is real. For state offices specifically, the State Government Telephone Directory lists numbers agency by agency, and directory assistance for state government answers at 800-256-7777 statewide or 225-342-6600 in Baton Rouge.