Short answer: Two.
TRICARE currently operates with two regional contracts TRICARE East and TRICARE West.
But if you’ve been around military healthcare for a while, you might be scratching your head right now thinking, “Wait, didn’t there used to be more?”
You’re absolutely right. And that confusion causes real problems for families, billers, and providers every single day.
Let me break this down the way I wish someone had explained it to me years ago.
Also Read: Military and Veteran Health Coverage Options Explained: TRICARE vs. CHAMPVA
The Current TRICARE Regional Structure (2024)
Here’s how it works now:
- TRICARE East – Managed by Humana Military
- TRICARE West – Managed by Health Net Federal Services
Each region covers about half of the United States, plus overseas areas are handled separately under TRICARE Overseas Program contractors.
You might be wondering — why only two regions?
According to the Department of Defense, consolidating into two large regions was supposed to streamline administration and improve consistency. Whether that actually happened is… debatable. Most billing managers I’ve talked to say it just shifted which problems they deal with.
What Happened to the Other Regions?
If you worked with TRICARE before 2017–2018, you’ll remember there used to be three regions: North, South, and West.
Here’s a quick timeline:
Before 2013: TRICARE had multiple smaller regions with different contractors.
2013–2017: The system shifted to three regions (North, South, West).
2017–2018: TRICARE consolidated into the current two-region system — East and West.
I still meet providers who haven’t updated their billing software to reflect this. They’ll try to submit claims under the old “TRICARE North” payer ID and wonder why everything gets rejected.
Never assume your clearinghouse has the updated payer database — I’ve seen offices lose weeks of revenue because of outdated region assignments.
Which States Are in TRICARE East vs. West?
This is where it gets messy.
TRICARE East includes:
Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Vermont, Virginia, West Virginia, Wisconsin, and Washington D.C.
TRICARE West includes:
Alaska, Arizona, California, Colorado, Hawaii, Idaho, Iowa, Kansas, Minnesota, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming.
Here’s a practical tip: Don’t memorize this list. Just bookmark the official TRICARE regional map on the TRICARE website. I keep it pinned in my browser because even after years in billing, I still look it up when onboarding a new beneficiary from a state we don’t usually see.
Why This Confuses Patients (And Staff)
Imagine this situation:
A military family moves from Virginia (TRICARE East) to California (TRICARE West). They call their old provider to transfer records. The provider’s office tries to verify eligibility using the East contractor’s portal, and it shows the patient as inactive.
Panic ensues.
The staff assumes the patient lost coverage. The patient thinks there’s a system error. In reality, the patient just switched regions, and the old region’s system won’t show them anymore.
I’ve seen this happen dozens of times.
What the person learned: Always verify eligibility using the main TRICARE website or MHS GENESIS, not the regional contractor portal, especially if the patient recently moved.
How to Find Out Which Region a Patient Is In
Here’s my specific workflow:
- Ask the patient their home ZIP code (not where they’re temporarily stationed their enrolled address).
- Use the TRICARE “Find Your Regional Contractor” tool on TRICARE.mil.
- If the tool is down (yes, it happens), call the main TRICARE phone line at 1-800-538-9552 they’ll route you to the correct region.
Option A vs. Option B:
- Option A: Use the TRICARE website tool — fast, accurate, always updated.
- Option B: Call the contractor directly — works, but you might get transferred if you called the wrong region.
I prefer Option A because phone hold times with TRICARE can be brutal, especially late in the month when everyone’s chasing claim statuses.
Common Mistakes When Billing Across TRICARE Regions
New billing staff often confuse the regional contract with the TRICARE plan type (Prime, Select, For Life, etc.). I used to do the same.
Here’s what happens:
You see a claim for a patient with TRICARE Prime. You assume they’re in your region because your office is in Texas. But the patient is enrolled in California so even though your office is in TRICARE East, you have to bill TRICARE West.
The region is determined by where the patient lives, not where the provider is located.
If you skip verifying the patient’s enrolled region, you’ll end up with a denial or the claim sitting in limbo for 60+ days while it gets forwarded to the correct contractor.
What About TRICARE Overseas?
Good question.
TRICARE Overseas is handled separately and split into:
- TRICARE Eurasia-Africa (managed by International SOS)
- TRICARE Pacific (also managed by International SOS)
These are NOT part of East or West.
If you’re billing for a beneficiary stationed overseas, don’t send the claim to Humana or Health Net it’ll get rejected. You need to submit to the overseas contractor.
Most billing managers agree that overseas claims are the trickiest to process. The time zone differences alone make follow-up a headache.
Tools I Actually Use to Track TRICARE Regions
We keep a shared Google Sheet with:
- Patient name
- Enrolled ZIP code
- Region (East/West/Overseas)
- Contractor name
- Last eligibility check date
It’s simple, but it works better than our old system where we’d have to dig through notes every time.
Some offices use fancy practice management systems that auto-populate region info. That’s great until the system doesn’t update when TRICARE changes contracts (which has happened before).
I strongly recommend maintaining a manual backup, even if it’s just a spreadsheet.
Have You Ever Noticed TRICARE Processes Claims Differently by Region?
Because they absolutely do.
In my experience:
- TRICARE East (Humana) tends to respond to online portal inquiries faster.
- TRICARE West (Health Net) sometimes processes paper claims quicker, but their phone support can have longer wait times.
This is anecdotal — your mileage may vary. But I’ve talked to enough billing coordinators at conferences to know I’m not imagining it.
Quick Warning: Regional Contracts Can Change
Here’s something new billers don’t always realize:
TRICARE contracts are rebid every several years.
That means the company managing TRICARE East today might not be the same one managing it in 2027.
When I first handled TRICARE billing, I used to think Humana and Health Net were permanent. Now I know these are just the current contractors. When contracts change, everything changes payer IDs, portals, phone numbers, mailing addresses.
If you’re not on the TRICARE provider email list, you might miss the transition notices. And trust me, you don’t want to be submitting claims to a contractor that’s no longer in the network.
FAQs Based on Real Questions I Get
Not by choice. Your region is based on your home address. If you move, your region changes automatically.
TRICARE uses the enrolled address on file with DEERS. That’s the one that determines the region. If the patient updates their address mid-year, the region could switch and yes, that can cause billing headaches.
Mostly, yes. TRICARE Prime, Select, Young Adult, and Retired Reserve all follow the East/West split. TRICARE For Life works a bit differently since it coordinates with Medicare, but the regional map still applies for admin purposes.
The claim usually gets forwarded to the correct region, but it adds 2–4 weeks of processing time. Sometimes it just denies, and you have to resubmit from scratch.
My Opinion on Best Practices
If I could give one piece of advice, it’s this:
Always verify the region before you submit the claim even if you’ve billed this patient before.
Military families move. A lot. And when they do, your billing process has to adapt instantly or you’re looking at denials, resubmissions, and frustrated patients.
I keep a sticky note on my monitor that says: “ZIP code = Region.”
Sounds silly, but it’s saved me more times than I can count.
Exceptions You Should Know About
Here’s something that trips people up:
TRICARE Reserve Select and TRICARE Retired Reserve members can live anywhere, but they’re still assigned to a region based on their address.
And here’s a contradiction: Even though TRICARE For Life beneficiaries are mostly dealing with Medicare as primary, they’re still technically enrolled in a TRICARE region and if you need to contact TRICARE about coordination of benefits, you have to go through the correct regional contractor.
Rules are not always absolute with TRICARE. There are always edge cases.
Risk of Getting the Region Wrong
Let me be blunt:
If you consistently bill the wrong TRICARE region, you will:
- Delay payments by 30–60 days
- Increase your denial rate
- Frustrate patients who then call you asking why their claim is taking forever
- Waste staff time on rework
Most payers respond faster between Tuesday and Thursday mid-morning (just a micro-detail I’ve noticed over the years). If you’re calling to fix a region-related issue, try calling around 10 AM EST you’ll usually get shorter hold times.
Final Thoughts
So, how many regions are in TRICARE?
Two: East and West.
But understanding how those regions work, how they’ve changed, and how to navigate them in real-world billing situations? That takes experience.
When I first started, I thought TRICARE was just another insurance. Now I know it’s a whole system unto itself and the regional structure is just the beginning.
If you work with TRICARE regularly, keep that regional map handy, double-check every patient’s ZIP code, and don’t assume anything stays the same year over year.
And if you’re a patient or family member trying to figure out which region you’re in just plug your ZIP code into the TRICARE website tool. It’ll save you a phone call and a lot of confusion.
Have questions about your specific region or billing situation? Drop a comment I’ll do my best to point you in the right direction.