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County road miles

Miles of road maintained by each Idaho county, by surface type, from the Idaho Transportation Department's Financial Planning & Analysis Section.

Figures

County-maintained road miles, 2010 to 2018County-maintained road miles, 2010 to 2018. Idaho: 27,981.663 in 2010, 28,011.751 in 2018.010k20k30k20102015IdahoMilesCounty-maintained road miles, 2010 to 2018County-maintained road miles, 2010 to 2018. Idaho: 27,981.663 in 2010, 28,011.751 in 2018.010k20k30k20102015IdahoMilesCounty-maintained road miles, 2010 to 2018County-maintained road miles, 2010 to 2018. Idaho: 27,981.663 in 2010, 28,011.751 in 2018.010k20k30k20102012201420162018IdahoMiles

Source: Idaho Transportation Department, Road Miles by County by Surface Type. Data period 2018. Published .

MeasureValuePeriod
County-maintained road miles201828,012 miles2018

Pages built on this dataset

Publisher

Organization
Idaho Transportation Department
Publisher’s dataset
Road Miles by County by Surface Type
File or API used
https://apps.itd.idaho.gov/apps/Fund/Local/SURTYPE18.pdf
Methodology
https://itd.idaho.gov/local-highway-dist-fund/

Coverage

Geography
Counties and Idaho
Time coverage
2010-2018
Update frequency
Annual, but not published since the 2018 edition as of this check.
Published
2018
Retrieved
September 13, 2026
License of the records
Idaho public record.
Rows
3,240 observations, 2010-2018

Measures

MeasureWhat it measuresUnit
County-maintained road milesTotal miles of road maintained by the county, all surface types.miles
County-maintained road miles by surface typeCounty-maintained road miles broken down by surface type.miles

Caveats

  • This is road mileage maintained by the county itself, not every public road within the county: state highways, city streets and roads under a separate highway district (such as the Ada County Highway District) are not counted here. It is the mileage the Idaho Transportation Department's Local Highway Distribution Fund uses to divide funding among counties and highway districts.
  • No edition has been published since the one covering 2018.
  • The 2012 report prints two negative figures with no explanation, and both are carried as printed: Shoshone County's Low Bitumen (-9.076 miles) and Washington County's Less Than One Inch Bitumen (-0.369 miles). Each county's printed total is consistent with them.

How to cite

Understand Idaho, “Road Miles by County by Surface Type”, compiled from Idaho Transportation Department, Road Miles by County by Surface Type. Retrieved September 13, 2026. https://understandidaho.com/data/itd-road-miles-by-county/.

Cite Idaho Transportation Department directly for the figures themselves.

This page was last updated .