A Tax Code Area (TCA), or Taxing Authority Group (TAG), is a unique combination of overlapping taxing districts. Each TCA is given a levy rate based on the taxing districts it encompasses; property tax is calculated by multiplying the assessed value of the property by the levy rate.
A TCA does not need to be contiguous and can occur separately in various parts of a county. However, TCAs only occur within a single county’s boundaries; the same TCA number found in different counties are referencing a different combination of taxing district.
Example:
Below is a visual representation of a subsection of TCA 001-0006 in eastern Boise, Ada County. TCA 001-0006 contains 8 taxing districts that overlap in space. If we were to travel slightly north, we would be outside of Boise Auditorium’s boundary and thus be within TCA 001-0005.
NOTE: TCA 001-0006 in Elmore County (or any county other than Ada) does not contain any of the same districts as below.
Data
Search below by year and county for:
– List of Changes (LOC): lists each change in a county’s map (i.e., audit, annexation, de-annexation, correction, creation, dissolution, etc.) – showing area affected and TCA change
– Description of Numbers (DON): lists all TCAs by number for each county and which districts are found in each TCA
– TCA maps by City (not available for 2023 – present)
DONs and LOCs are published each year around March.
Selecting the County as “Statewide” will return statewide annexation and TCA shapefiles (not available every year).