US Census Geographic Boundaries

Cloud-optimized formats for Draft CalEnviroScreen 5.0 (released January 2026) is a cumulative environmental pollution and health vulnerability screening tool developed by California's Office of Environmental Health Hazard Assessment (OEHHA).

Product Details

Visibility: Public
Owner: Carl Boettiger
Created: 16 Jun 2026
Last Updated: 16 Jun 2026

Product Contents

sldl-README.md

Product Details

Product Contents

US Census Geographic Boundaries

Product Details

Visibility: Public
Owner: Carl Boettiger
Created: 16 Jun 2026
Last Updated: 16 Jun 2026

Product Contents

sldl-README.md

Name: sldl-README.md
Size: 5.04 KB
Content Type: text/markdown; charset=utf-8
Last Modified: 16 Jun 2026
Source URL: https://data.source.coop/cboettig/census/census-2025/sldl/README.md/sldl-README.md
Cloud URI: s3://us-west-2.opendata.source.coop/cboettig/census/census-2025/sldl/README.md/sldl-README.md

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Name: sldl-README.md
Size: 5.04 KB
Content Type: text/markdown; charset=utf-8
Last Modified: 16 Jun 2026
Source URL: https://data.source.coop/cboettig/census/census-2025/sldl/README.md/sldl-README.md
Cloud URI: s3://us-west-2.opendata.source.coop/cboettig/census/census-2025/sldl/README.md/sldl-README.md

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US Census 2025 State Legislative Districts — Lower Chamber (SLDL)

2025 state lower chamber legislative district boundaries from the US Census Bureau's TIGER/Line shapefiles, processed into cloud-native formats with H3 hexagonal spatial indexing.

Dataset Overview

Source: US Census Bureau TIGER/Line 2025
Geography Level: State Legislative District — Lower Chamber
Features: 4,879 districts
Coverage: 50 states + Puerto Rico (excludes DC and Nebraska — both unicameral)
H3 Resolution: 10 (~0.015 km² per hex)
Parent Resolutions: 9, 8, 0
Last Updated: March 2026

Available Formats

GeoParquet

s3://public-census/census-2025/sldl.parquet

Format: GeoParquet with ZSTD compression
CRS: EPSG:4326 (WGS84)
Row Groups: 100,000 features
Geometry Type: MultiPolygon
Use Case: Analytical queries with DuckDB, Polars, GeoPandas

PMTiles

s3://public-census/census-2025/sldl.pmtiles

Format: PMTiles v3
Source Layer: sldl
Use Case: Web map visualization with MapLibre GL JS, Leaflet

H3 Hex Index

s3://public-census/census-2025/sldl/hex/h0={cell}/

Format: Partitioned Parquet by H3 resolution 0 cells
Columns: h3_cell (resolution 10), feature_id, plus parent resolutions
Use Case: Fast spatial joins, area-weighted aggregation

Public HTTP Access

Attributes

Column	Type	Description
`_cng_fid`	int64	Unique feature ID (synthetic)
`STATEFP`	string	State FIPS code (2 digits)
`SLDLST`	string	State legislative district (lower) code
`GEOID`	string	Full geographic identifier (STATEFP + SLDLST)
`GEOIDFQ`	string	Fully qualified geographic identifier
`NAMELSAD`	string	Full district name with description
`LSAD`	string	Legal/Statistical Area Description code
`LSY`	string	Legislative session year
`MTFCC`	string	MAF/TIGER Feature Class Code (G5210)

Usage Examples

DuckDB Query

MapLibre GL JS

Point-in-District Spatial Join (DuckDB + H3)

Notes

Nebraska (FIPS 31) and DC (FIPS 11) are unicameral and have no lower chamber — they are absent from this dataset. See sldu-README.md for upper chamber data.
Puerto Rico (FIPS 72) is included.
This dataset is updated annually. The S3 path includes the vintage year (census-2025/) for reproducibility; prior vintages remain accessible.

Citation

U.S. Census Bureau (2025). TIGER/Line Shapefiles: State Legislative Districts (Lower Chamber). Retrieved from https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html

License

Public domain. No restrictions on use.

US Census 2025 State Legislative Districts — Lower Chamber (SLDL)

2025 state lower chamber legislative district boundaries from the US Census Bureau's TIGER/Line shapefiles, processed into cloud-native formats with H3 hexagonal spatial indexing.

Dataset Overview

Source: US Census Bureau TIGER/Line 2025
Geography Level: State Legislative District — Lower Chamber
Features: 4,879 districts
Coverage: 50 states + Puerto Rico (excludes DC and Nebraska — both unicameral)
H3 Resolution: 10 (~0.015 km² per hex)
Parent Resolutions: 9, 8, 0
Last Updated: March 2026

Available Formats

GeoParquet

s3://public-census/census-2025/sldl.parquet

Format: GeoParquet with ZSTD compression
CRS: EPSG:4326 (WGS84)
Row Groups: 100,000 features
Geometry Type: MultiPolygon
Use Case: Analytical queries with DuckDB, Polars, GeoPandas

PMTiles

s3://public-census/census-2025/sldl.pmtiles

Format: PMTiles v3
Source Layer: sldl
Use Case: Web map visualization with MapLibre GL JS, Leaflet

H3 Hex Index

s3://public-census/census-2025/sldl/hex/h0={cell}/

Format: Partitioned Parquet by H3 resolution 0 cells
Columns: h3_cell (resolution 10), feature_id, plus parent resolutions
Use Case: Fast spatial joins, area-weighted aggregation

Public HTTP Access

Attributes

Column	Type	Description
`_cng_fid`	int64	Unique feature ID (synthetic)
`STATEFP`	string	State FIPS code (2 digits)
`SLDLST`	string	State legislative district (lower) code
`GEOID`	string	Full geographic identifier (STATEFP + SLDLST)
`GEOIDFQ`	string	Fully qualified geographic identifier
`NAMELSAD`	string	Full district name with description
`LSAD`	string	Legal/Statistical Area Description code
`LSY`	string	Legislative session year
`MTFCC`	string	MAF/TIGER Feature Class Code (G5210)

Usage Examples

DuckDB Query

MapLibre GL JS

Point-in-District Spatial Join (DuckDB + H3)

Notes

Nebraska (FIPS 31) and DC (FIPS 11) are unicameral and have no lower chamber — they are absent from this dataset. See sldu-README.md for upper chamber data.
Puerto Rico (FIPS 72) is included.
This dataset is updated annually. The S3 path includes the vintage year (census-2025/) for reproducibility; prior vintages remain accessible.

Citation

U.S. Census Bureau (2025). TIGER/Line Shapefiles: State Legislative Districts (Lower Chamber). Retrieved from https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html

License

Public domain. No restrictions on use.

1https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet
2https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.pmtiles
3https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl/hex/h0=*/

1https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet
2https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.pmtiles
3https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl/hex/h0=*/

1LOAD spatial;
2
3-- All lower chamber districts in California
4SELECT SLDLST, NAMELSAD, ALAND / 1e6 AS land_km2
5FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet')
6WHERE STATEFP = '06'
7ORDER BY SLDLST;
8
9-- Largest districts by land area
10SELECT STATEFP, NAMELSAD, ALAND / 1e6 AS land_km2
11FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet')
12ORDER BY ALAND DESC
13LIMIT 10;
14
15-- Count districts per state
16SELECT STATEFP, COUNT(*) AS district_count
17FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet')
18GROUP BY STATEFP
19ORDER BY STATEFP;

1LOAD spatial;
2
3-- All lower chamber districts in California
4SELECT SLDLST, NAMELSAD, ALAND / 1e6 AS land_km2
5FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet')
6WHERE STATEFP = '06'
7ORDER BY SLDLST;
8
9-- Largest districts by land area
10SELECT STATEFP, NAMELSAD, ALAND / 1e6 AS land_km2
11FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet')
12ORDER BY ALAND DESC
13LIMIT 10;
14
15-- Count districts per state
16SELECT STATEFP, COUNT(*) AS district_count
17FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet')
18GROUP BY STATEFP
19ORDER BY STATEFP;

1INSTALL h3 FROM community; LOAD h3;
2LOAD spatial;
3
4-- Assign points to lower chamber districts via H3 join
5SELECT d.STATEFP, d.NAMELSAD, COUNT(*) AS point_count
6FROM (
7  SELECT h3_latlng_to_cell(lat, lon, 10) AS h3_cell FROM my_points
8) pts
9JOIN read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl/hex/h0=*/') h
10  ON pts.h3_cell = h.h3_cell
11JOIN read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet') d
12  ON h.feature_id = d._cng_fid
13GROUP BY d.STATEFP, d.NAMELSAD
14ORDER BY point_count DESC;

1INSTALL h3 FROM community; LOAD h3;
2LOAD spatial;
3
4-- Assign points to lower chamber districts via H3 join
5SELECT d.STATEFP, d.NAMELSAD, COUNT(*) AS point_count
6FROM (
7  SELECT h3_latlng_to_cell(lat, lon, 10) AS h3_cell FROM my_points
8) pts
9JOIN read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl/hex/h0=*/') h
10  ON pts.h3_cell = h.h3_cell
11JOIN read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.parquet') d
12  ON h.feature_id = d._cng_fid
13GROUP BY d.STATEFP, d.NAMELSAD
14ORDER BY point_count DESC;

1map.addSource('sldl', {
2  type: 'vector',
3  url: 'pmtiles://https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.pmtiles'
4});
5
6map.addLayer({
7  id: 'sldl-fill',
8  type: 'fill',
9  source: 'sldl',
10  'source-layer': 'sldl',
11  paint: {
12    'fill-color': '#4e79a7',
13    'fill-opacity': 0.3
14  }
15});
16
17map.addLayer({
18  id: 'sldl-outline',
19  type: 'line',
20  source: 'sldl',
21  'source-layer': 'sldl',
22  paint: {
23    'line-color': '#4e79a7',
24    'line-width': 1
25  }
26});

1map.addSource('sldl', {
2  type: 'vector',
3  url: 'pmtiles://https://s3-west.nrp-nautilus.io/public-census/census-2025/sldl.pmtiles'
4});
5
6map.addLayer({
7  id: 'sldl-fill',
8  type: 'fill',
9  source: 'sldl',
10  'source-layer': 'sldl',
11  paint: {
12    'fill-color': '#4e79a7',
13    'fill-opacity': 0.3
14  }
15});
16
17map.addLayer({
18  id: 'sldl-outline',
19  type: 'line',
20  source: 'sldl',
21  'source-layer': 'sldl',
22  paint: {
23    'line-color': '#4e79a7',
24    'line-width': 1
25  }
26});

US Census Geographic Boundaries

US Census Geographic Boundaries

US Census 2025 State Legislative Districts — Lower Chamber (SLDL)

Dataset Overview

Available Formats

GeoParquet

PMTiles

H3 Hex Index

Public HTTP Access

Attributes

Usage Examples

DuckDB Query

MapLibre GL JS

Point-in-District Spatial Join (DuckDB + H3)

Notes

Citation

License

Related Datasets

US Census 2025 State Legislative Districts — Lower Chamber (SLDL)

Dataset Overview

Available Formats

GeoParquet

PMTiles

H3 Hex Index

Public HTTP Access

Attributes

Usage Examples

DuckDB Query

MapLibre GL JS

Point-in-District Spatial Join (DuckDB + H3)

Notes

Citation

License

Related Datasets