Convert TIGER/Line dataset of the US Census Bureau to CSV files which can be imported by Nominatim. In Nominatim the created tables are separate from OpenStreetMap tables and get queried at search time separately.

The dataset gets updated once per year. Downloading is prone to be slow (can take a full day) and converting them can take hours as well. There's a mirror on https://downloads.opencagedata.com/public/

Replace '2021' with the current year throughout.

1. Install the GDAL library and python bindings and the unzip tool

   # Ubuntu:
   sudo apt-get install python3-gdal python3-pip unzip
   pip3 install -r requirements.txt

2. Get the TIGER 2023 data. You will need the EDGES files (3,235 zip files, 11GB total).

   wget -r ftp://ftp2.census.gov/geo/tiger/TIGER2023/EDGES/
   

3. Convert the data into CSV files. Adjust the file paths in the scripts as needed

   ./convert.sh

4. Maybe: package the created files

   tar -czf tiger2023-nominatim-preprocessed.csv.tar.gz tiger

Addtionally create a us_postcodes.csv.gz file with centroid coordinates.

cat tiger/*.csv | ./calculate_postcode_centroids.py | gzip -9 > us_postcodes.csv.gz

The source code is available under a GPLv2 license.