Most Expensive Counties to Live in the U.S.

Current #1 in this ranking

In the model, a more expensive location like San Mateo County, CA has a cost-of-living index of 100 (U.S. = 100) and median rent around $2,749/mo. The estimated salary needed to live comfortably is about $109,940/yr, which is below the local median income; the biggest estimated monthly driver is Rent (housing). In this area (mid-range), the model’s rent math puts housing in a “Moderate” bucket: rent is meaningful, so budgeting matters and rent (housing) is the main lever in the estimates.

Cost-of-living tier: moderate

What drives the budget here?

This area is generally mid-range based on a cost-of-living index of 100 (U.S. average = 100). Typical rent-to-gross is in the Moderate range (using the page’s rent and income inputs).

In the site’s estimated monthly breakdown, the largest category is Rent (housing) (2,748.5/mo), so that’s the biggest lever for moving the overall budget up or down.

Practical next steps

• Rent is meaningful but still near the affordability guideline. A small move to a lower-rent neighborhood (or a higher gross income) can make the budget feel much steadier.
• State income tax is on the higher side in this state (9.3%). That reduces take-home pay, so “affordable” decisions should be based on net income, not just gross.
• In this area, the modeled rent target is reachable at (or below) the local median income level.