The 4-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the second level hydrologic subdivision of the United States. A 4-digit hydrologic unit includes the area drained by a river system, a reach of a river and its tributaries in that reach, a closed basin(s), or a group of streams forming a coastal drainage area. There are 240 4-digit hydrologic units with an average size of 17,521 square miles (45,378 sq. km.).
Watershed Boundary Dataset, 6-Digit Hydrologic Units
The 6-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the third level hydrologic subdivision of the United States. A 6-digit hydrologic unit may subdivide a 4-digit hydrologic unit or may be equivalent. There are 401 6-digit hydrologic units with an average size of 10,486 square miles (27,159 sq. km.).
Watershed Boundary Dataset, 8-Digit Hydrologic Units
The 8-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the fourth level hydrologic subdivision of the United States. A hydrologic unit can accept surface water from upstream drainage areas and may define a drainage area with single or multiple outlet points. An 8-digit hydrologic unit, or sub-basin, is a common management unit for water resource planning and analysis. There are 2,362 8-digit hydrologic units with an average size of 1,783 square miles (4,619 sq. km.).
Data from the 2020 County Health Rankings are here!
Data and maps from the 2020 County Health Rankings are now available! Click the map below to view the rank and underlying data for Premature Death, or search for additional updates by searching the Map Room for the term “CHR 2020”.
Ecoegions
Ecoregions are identified by analyzing the patterns and composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity (Omernik 1987, 1995). These phenomena include geology, landforms, soils, vegetation, climate, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral classification scheme has been adopted for different hierarchical levels of ecoregions, ranging from general regions to more detailed:
Level I – 12 ecoregions in the continental U.S.
Level II – 25 ecoregions in the continental U.S.
Level III -105 ecoregions in the continental U.S.
Level IV – 967 ecoregions in the conterminous U.S.
Explanations of the methods used to define these multi-agency ecoregions are given in Omernik and Griffith (2014), Omernik (1995, 2004), and CEC (1997).
Locations of Dental Care Providers
This layer displays the locations of all dental health care providers with a CMS National Provider Identifier (NPI). Data are from the Centers for Medicare and Medicaid Services (CMS) February 2020 National Provider Identifier (NPI) downloadable file.
Locations of Addiction/Substance Abuse Providers
This layer displays the locations of all addiction or substance abuse providers with a CMS National Provider Identifier (NPI). Addiction or substance abuse providers include MDs, DOs, and other credentialed professionals specializing substance abuse treatment, rehabilitation, addiction medicine, or providing methadone. Data are from the Centers for Medicare and Medicaid Services (CMS) February 2020 National Provider Identifier (NPI) downloadable file.
Locations of Primary Care Physicians
This layer displays the locations of all dental health care health care professional providing primary care with a CMS National Provider Identifier (NPI). Data are from the Centers for Medicare and Medicaid Services (CMS) February 2020 National Provider Identifier (NPI) downloadable file.
Fast Food Restaurant Rates by County and ZIP Code Tabulation Area, 2017
This layer displays rates and counts of fast food and limited-service eating establishments in counties across the United States. Establishment counts are acquired from the 2017 County Business Patterns, released by the US Census Bureau in November and December, 2019. Rates are calculated per 100,000 population based on figures from the 2010 Decennial Census. For more map layers from this series, search the Map Room for the terms County Business Patterns or CBP .
FCC Broadband Access
This layer displays Broadband access information at the County, Tract, and Block Group Level as of June, 2019.