There were 3,993 total businesses in the county zip codes, with 848 construction businesses (21.2%) accounting for the largest proportion of these businesses. 2,177 businesses (54.5%) had fewer than five employees, and 19 (0.5%) had 250 or more.
The county with the largest median business size was Nez Perce County. Median-sized businesses in Nez Perce County was between five and nine.
The following table shows the median business size in all Idaho counties.