Idaho County Map

Idaho County Statistics & Summary

How Idaho Counties and 5-Digit FIPS Codes Work

In U.S. Census Bureau TIGER/Line geography, Idaho (ID) is assigned the 2-digit state Federal Information Processing Series (FIPS) code 16 and covers 82,645 square miles of land area across 44 counties in the Mountain Time (MT); northern Idaho is in Pacific Time (PT) zone (with Boise as the state capital). Every county in the directory above carries a unique 5-digit GEOID formed by combining state prefix 16 with a 3-digit county code (ranging alphabetically from Ada County at 16001 to Washington County at 16087).

Because U.S. Postal Service 5-digit ZIP Codes follow mail carrier delivery routes rather than local government borders, many postal addresses in Idaho carry a neighboring city’s mailing name or sit inside a multi-county ZIP Code Tabulation Area (ZCTA). Property tax assessments, deed recording, circuit and county court venue, voter registration precincts, sheriff jurisdiction, and county sales tax rates in Idaho are determined by the legal county boundary shown on the map above rather than the postal city name on an envelope.

Land area figures in square miles and internal centroid coordinates (INTPTLAT, INTPTLON) come directly from the U.S. Census Bureau’s current TIGERweb State_County benchmark, while 44 administrative seats and 44 verified official government websites are cross-referenced from Wikidata (CC0). Need a clean outline worksheet without county labels, or want to verify which Idaho county a specific home or business address sits in? Open the Blank Map of Idaho, run a street-segment check on Address to County Lookup, check multi-county postal overlap on ZIP Code to County Lookup, or browse all 50 states on the National U.S. County Map.

Adjacent State County Maps

Explore county maps and FIPS directories for states bordering Idaho:

• Montana Counties MT
• Nevada Counties NV
• Oregon Counties OR
• Utah Counties UT
• Washington Counties WA
• Wyoming Counties WY