This layer displays information about residents of assisted housing properties in counties across the US. Characteristics include the percent of disabled, elderly, and single-parents in assisted housing facilities.
The 2-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the major water resource regions of the United States. A water resource region is the first level of classification used by the United States Geological Survey to divide and sub-divide the United States into successively smaller hydrologic units. This first level of classification divides the United States into 22 major geographic areas, or regions. These geographic areas contain either the drainage area of a major river or the combined drainage areas of a series of rivers.
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 hydrololgic units with an average size of 17,521 square miles (45,378 sq. km.).
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 hyrologic unit or may be equivalent. There are 401 6-digit hydrololgic units with an average size of 10,486 square miles (27,159 sq. km.).
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 hydrololgic units with an average size of 1,783 square miles (4,619 sq. km.).
The 10-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the fifth 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. A 10-digit hydrologic unit, or watershed, divides sub-basins into smaller management areas. There are 18,679 10-digit hydrololgic units with an average size of 226 square miles (585 sq. km.).
The 12-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the sixth 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. A 12-digit hydrologic unit, or subwatershed, supports water resource management and planning activities at a localized and site-specific level. There are 101,779 12-digit hydrololgic units with an average size of 41 square miles (107 sq. km.).
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 .
Data and maps from the 2020 County Health Rankings are now availble! 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”.
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).