Idaho's Jumbo Line Moves in Exactly One County
Program and regulatory figures verified September 25, 2026. Details change; confirm your scenario with us.
Idaho has one high-cost county and it is not the one most people would guess. Sun Valley is at the baseline; the Teton Valley is not.
The 2026 limits
| County | One-unit limit | Note |
|---|---|---|
| Teton | $1,249,125 | Driggs, Victor. CBSA 27220 with Jackson, WY. Two-unit $1,599,375 |
| Ada | $832,750 | Boise, Meridian, Eagle |
| Kootenai | $832,750 | Coeur d'Alene, Post Falls |
| Blaine | $832,750 | Sun Valley, Ketchum, Hailey |
| Bonneville | $832,750 | Idaho Falls |
| Canyon, Twin Falls, Bannock, Latah, Nez Perce, Madison, Valley | $832,750 | Baseline |
Why Teton County is the outlier
Conforming limits are set by metropolitan area rather than by state. Teton County, Idaho sits in CBSA 27220, the Jackson, Wyoming-Idaho area, and inherits that area's high-cost limit. The result is that Driggs and Victor, on the Idaho side of the Tetons, carry a conforming ceiling $416,375 higher than anywhere else in Idaho.
For a move-up that is decisive. A purchase that would be jumbo in Ada County can be conforming in Teton County, and conforming means the published departing-residence rules in Fannie Mae B3-3.8-05 apply rather than an investor's own. See the Teton Valley page.
And why Blaine County is not
Sun Valley and Ketchum are Idaho's best-known resort destinations, and Blaine County sits at the $832,750 baseline. Buyers there are more likely to cross into jumbo than buyers in the Teton Valley, which is the reverse of what the reputations suggest.
The lesson is narrow and practical: check the county in the FHFA file rather than reasoning from how expensive a place feels.
What changes above the line
Jumbo guidelines come from individual investors, so specifics vary. Three patterns hold well enough to plan around:
- Deeper reserves, with the departing residence adding its own requirement.
- Tighter treatment of the departing payment. The rental-offset path in B3-3.8-05 is an agency rule; some jumbo investors will not remove a departing payment until the sale actually funds.
- More documentation of the exit, meaning how and when the departing home is expected to sell gets underwritten rather than assumed.
Above the line, carrying both payments with a later recast is often the most reliable structure because it does not depend on an investor accepting an offset. See the structures page.
Headroom in the rest of Idaho
Even Coeur d'Alene, Idaho's priciest metro at $605,220 as of August 2026, has roughly $227,000 of room under the baseline. Boise City at $493,522 has about $339,000. For most Idaho move-ups the loan limit is not the constraint; the debt-to-income ratio is. See qualifying without selling and the market page.
Frequently asked questions
What is the conforming loan limit in Teton County, Idaho for 2026?
$1,249,125 on one unit and $1,599,375 on two units. Teton County sits in CBSA 27220, the Jackson, Wyoming-Idaho area, and inherits that area's high-cost limit. It is $416,375 above the $832,750 baseline applying in Idaho's other 43 counties.
Is Sun Valley in a high-cost county for conforming limits?
No. Blaine County, which contains Sun Valley, Ketchum and Hailey, sits at the $832,750 baseline. Teton County on Idaho's eastern border is the state's only county above baseline, which is the opposite of what the two areas' reputations suggest.
Which Idaho counties are above the baseline conforming limit?
Only Teton County, at $1,249,125 one-unit. The other 43 counties in the FHFA 2026 file, including Ada, Kootenai, Bonneville, Canyon, Twin Falls, Bannock and Blaine, are all at $832,750.
Does jumbo financing change how my departing Idaho home is treated?
Generally yes. The departing-residence rules in Fannie Mae B3-3.8-05 are agency guidelines; jumbo investors set their own, tend to require deeper reserves, and some will not remove the departing payment until the sale funds. Carrying both payments with a later recast is often more reliable above the line.
Mike Certo · NMLS #260555 · Cornerstone First Mortgage NMLS #173855 · Equal Housing Lender. Educational content about financing, not a loan commitment and not legal, tax, or real estate advice. Idaho's homeowner's exemption is administered county by county under Idaho Code 63-602G and 63-703, and eligibility depends on your facts; your county assessor, your CPA or an Idaho attorney, and your real estate agent each handle their own part. Loans are subject to borrower and property qualification.