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

sldu-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

sldu-README.md

Name: sldu-README.md
Size: 5.1 KB
Content Type: text/markdown; charset=utf-8
Last Modified: 16 Jun 2026
Source URL: https://data.source.coop/cboettig/census/census-2025/sldu/README.md/sldu-README.md
Cloud URI: s3://us-west-2.opendata.source.coop/cboettig/census/census-2025/sldu/README.md/sldu-README.md

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Name: sldu-README.md
Size: 5.1 KB
Content Type: text/markdown; charset=utf-8
Last Modified: 16 Jun 2026
Source URL: https://data.source.coop/cboettig/census/census-2025/sldu/README.md/sldu-README.md
Cloud URI: s3://us-west-2.opendata.source.coop/cboettig/census/census-2025/sldu/README.md/sldu-README.md

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US Census 2025 State Legislative Districts — Upper Chamber (SLDU)

2025 state upper 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 — Upper Chamber
Features: 1,964 districts
Coverage: 50 states + DC + Nebraska + Puerto Rico (52 jurisdictions)
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/sldu.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/sldu.pmtiles

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

H3 Hex Index

s3://public-census/census-2025/sldu/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)
`SLDUST`	string	State legislative district (upper) code
`GEOID`	string	Full geographic identifier (STATEFP + SLDUST)
`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 (G5200)

Usage Examples

DuckDB Query

MapLibre GL JS

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

Notes

Nebraska (FIPS 31) uses a unicameral legislature — its single chamber is represented here as the upper chamber.
DC (FIPS 11) is included (DC Council).
Puerto Rico (FIPS 72) is included.
Upper chamber districts are larger and fewer than lower chamber districts (1,964 vs 4,879 nationally).
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 (Upper 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 — Upper Chamber (SLDU)

2025 state upper 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 — Upper Chamber
Features: 1,964 districts
Coverage: 50 states + DC + Nebraska + Puerto Rico (52 jurisdictions)
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/sldu.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/sldu.pmtiles

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

H3 Hex Index

s3://public-census/census-2025/sldu/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)
`SLDUST`	string	State legislative district (upper) code
`GEOID`	string	Full geographic identifier (STATEFP + SLDUST)
`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 (G5200)

Usage Examples

DuckDB Query

MapLibre GL JS

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

Notes

Nebraska (FIPS 31) uses a unicameral legislature — its single chamber is represented here as the upper chamber.
DC (FIPS 11) is included (DC Council).
Puerto Rico (FIPS 72) is included.
Upper chamber districts are larger and fewer than lower chamber districts (1,964 vs 4,879 nationally).
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 (Upper 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/sldu.parquet
2https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu.pmtiles
3https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu/hex/h0=*/

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

1LOAD spatial;
2
3-- All upper chamber districts in Texas
4SELECT SLDUST, NAMELSAD, ALAND / 1e6 AS land_km2
5FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu.parquet')
6WHERE STATEFP = '48'
7ORDER BY SLDUST;
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/sldu.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/sldu.parquet')
18GROUP BY STATEFP
19ORDER BY STATEFP;

1LOAD spatial;
2
3-- All upper chamber districts in Texas
4SELECT SLDUST, NAMELSAD, ALAND / 1e6 AS land_km2
5FROM read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu.parquet')
6WHERE STATEFP = '48'
7ORDER BY SLDUST;
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/sldu.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/sldu.parquet')
18GROUP BY STATEFP
19ORDER BY STATEFP;

1INSTALL h3 FROM community; LOAD h3;
2LOAD spatial;
3
4-- Assign points to upper 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/sldu/hex/h0=*/') h
10  ON pts.h3_cell = h.h3_cell
11JOIN read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu.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 upper 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/sldu/hex/h0=*/') h
10  ON pts.h3_cell = h.h3_cell
11JOIN read_parquet('https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu.parquet') d
12  ON h.feature_id = d._cng_fid
13GROUP BY d.STATEFP, d.NAMELSAD
14ORDER BY point_count DESC;

1map.addSource('sldu', {
2  type: 'vector',
3  url: 'pmtiles://https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu.pmtiles'
4});
5
6map.addLayer({
7  id: 'sldu-fill',
8  type: 'fill',
9  source: 'sldu',
10  'source-layer': 'sldu',
11  paint: {
12    'fill-color': '#e15759',
13    'fill-opacity': 0.3
14  }
15});
16
17map.addLayer({
18  id: 'sldu-outline',
19  type: 'line',
20  source: 'sldu',
21  'source-layer': 'sldu',
22  paint: {
23    'line-color': '#e15759',
24    'line-width': 1
25  }
26});

1map.addSource('sldu', {
2  type: 'vector',
3  url: 'pmtiles://https://s3-west.nrp-nautilus.io/public-census/census-2025/sldu.pmtiles'
4});
5
6map.addLayer({
7  id: 'sldu-fill',
8  type: 'fill',
9  source: 'sldu',
10  'source-layer': 'sldu',
11  paint: {
12    'fill-color': '#e15759',
13    'fill-opacity': 0.3
14  }
15});
16
17map.addLayer({
18  id: 'sldu-outline',
19  type: 'line',
20  source: 'sldu',
21  'source-layer': 'sldu',
22  paint: {
23    'line-color': '#e15759',
24    'line-width': 1
25  }
26});

US Census Geographic Boundaries

US Census Geographic Boundaries

US Census 2025 State Legislative Districts — Upper Chamber (SLDU)

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 — Upper Chamber (SLDU)

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