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COCHomeless

Datasets and spatial tools for United States homelessness research. COCHomeless packages HUD Continuum of Care (CoC) Point-in-Time (PIT) homeless counts, CoC boundaries, a Census-to-CoC crosswalk, and county-level homeless estimates, covering 2007–2025.

Installation

# install.packages("remotes")
remotes::install_github("SSDALab/COCHomeless", build_vignettes = TRUE)
library(COCHomeless)

sf is required (spatial objects). tidycensus, ggplot2, tigris, imputeTS and a few others are only needed to rebuild data or run the vignettes.

Coverage

All series run 2007 through 2025 (annual). The 2025 PIT counts are HUD's official release; hud2025_prelim keeps the earlier Community Solutions estimate for reference. In 2021 HUD waived the unsheltered count for many CoCs during COVID-19, so 2021 understates homelessness — the vignettes show an ARIMA reconstruction.

Three forms of data

1. CoC level (HUD administrative areas)

Object What
hud2007hud2025 PIT "Overall Homeless" count per CoC, by year
coc2007coc2025 CoC boundary polygons (national sf), by year
coc_mergers CoC merger crosswalk over time (code lineage)
pit_us national totals split into sheltered / unsheltered
pit_coc per-CoC sheltered / unsheltered / total, 2007–2025
pit_coc_detail per-CoC by shelter type × subpopulation (veterans, chronic, youth, families, gender, race, age)
hud2025_prelim preliminary 2025 estimate (superseded by hud2025)

CoC boundaries (coc20XX) also carry that year's total/sheltered/unsheltered.

2. Census ↔ CoC crosswalk (links Census tracts/counties to CoCs)

Object What
tract_coc2007tract_coc2025 tract → CoC hard assignment, by year
tract_coc_wt2007tract_coc_wt2025 tract ↔ CoC area weights, by year
county_coc2007county_coc2025 county ↔ CoC weights (both directions), by year

Tract geography uses 2010-census tracts for 2007–2019 and 2020-census tracts for 2020–2025.

3. County-level estimates (CoC counts disaggregated to counties)

Object What
homeless county estimates count07count25 + ACS covariates (imputed)
homeless_na same, before imputation (missing counties as NA)
sp_homeless homeless as sf, also carrying sheltered<yy>/unsheltered<yy>
county_pit county sheltered / unsheltered / total, 2007–2025 (long)
county_pit_detail county by shelter type × subpopulation (gender, race, age, …)
counties, states full-US sf base layers
area county land area (km²)

Vignettes

After installing with build_vignettes = TRUE:

browseVignettes("COCHomeless")
  • CoC Point-in-Time homeless counts (coc-pit-counts) — national & state maps, per-CoC trends, sheltered/unsheltered series with ARIMA reconstruction of 2021.
  • County-level homeless estimates (county-estimates) — county-vs-CoC comparison, per-capita maps, US/CA/WA trends, a 2025 summary grid.
  • Census-to-CoC crosswalk (census-coc-crosswalk) — using the crosswalk and coc_mergers.

Vignette sources are in vignettes/; build scripts that regenerate every dataset from source are in data-raw/.

Methodology & citation

County estimates disaggregate CoC PIT counts by population density and impute counties with no CoC, following Almquist, Helwig & You (2020). Please cite:

Almquist, Z. W., Helwig, N. E., & You, Y. (2020). Connecting Continuum of Care point-in-time homeless counts to United States Census areal units. Mathematical Population Studies, 27(1), 46–58. https://doi.org/10.1080/08898480.2019.1636574

The Census-to-CoC crosswalk follows Tom Byrne's HUD-CoC-Geography-Crosswalk; please credit it when using the tract_coc* / county_coc* data. Run citation("COCHomeless") for full details.

ACS pulls need a Census API key in ~/.Renviron (CENSUS_API_KEY); never commit it.

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Spatial data for US Point-in-Time data for people experiencing homelessness

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