Franklin County, Idaho

Franklin County population, land area and income

Franklin County had 15,638 residents in the Census Vintage 2024 estimate, on 663.0 square miles of land. It ranks 22nd of 44 in Idaho by population and 37th by land area. That works out to 23.6 people per square mile, below the US average of 96.3, and below the national county median.

The median county-equivalent in Idaho has 15,019 residents, about the same as Franklin County.

Its SAIPE 2023 median household income of $80,768 is in the top quarter among 3,143 counties with an estimate.

How Franklin County's population changed since 2020

Franklin County gained 1,355 residents between the July 2020 and July 2024 estimates, a rise of 9.5%. That ranks 11th of 44 in Idaho for growth. The median Idaho county changed by +7.2%, and the state as a whole by +8.2%.

Since the April 2020 estimates base, Franklin County recorded 953 births and 543 deaths, a natural change of +410. Net international migration added +25 and net domestic migration, people moving to or from other US counties, came to +1,009. The largest single component was domestic migration, which added 1,009 people.

Where Franklin County is

The Census internal point of Franklin County is at 42.173600, -111.823000. It sits in UTM zone 12N. The map shades Idaho's 44 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Franklin County outlined. Dots are towns of 1,000+ people with residents in it.

Towns in Franklin County

2 incorporated places of 1,000+ people have residents in Franklin County, 7,288 people together, or 47% of the county. Each figure counts only the part of the town inside Franklin County; towns marked "part" extend into another county. The largest is Preston with 6,160.

Counties bordering Franklin County

The Census 2024 county adjacency file lists 6 neighbors for Franklin County, including 2 across a state line. The most populous is Cache County, UT, with 145,487 residents. Distances run between Census internal points in a straight line.

• UT

  Cache County, UT

  145,487 people

  31 mi S

• Bannock County

  91,010 people

  41 mi NNW

• Caribou County

  7,239 people

  45 mi NNE

• Bear Lake County

  6,779 people

  27 mi ENE

• Oneida County

  4,976 people

  36 mi W

• UT

  Rich County, UT

  2,752 people

  48 mi SE

Distance to Boise and the nearest big city

Boise is 243.6 miles WNW of Franklin County's internal point in a straight line. The nearest place of 100,000 or more is Salt Lake City, UT (population 217,783), 96.7 miles away. The nearest place of 10,000 or more is Smithfield, UT (population 15,018), 23.4 miles away.

Franklin County FIPS code

The FIPS code of Franklin County is 16041: state code 16 for Idaho plus county code 041. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $80,768.