2 Sep 2025

Natural Gas Pipelines

The U.S. natural gas pipeline network is a highly integrated network that moves natural gas throughout the continental United States. The pipeline network has about 3 million miles of mainline and other pipelines that link natural gas production areas and storage facilities with consumers. In 2017, this natural gas transportation network delivered about 25 trillion cubic feet (Tcf) of natural gas to 75 million customers.

About half of the existing mainline natural gas transmission network and a large portion of the local distribution network were installed in the 1950s and 1960s because consumer demand for natural gas more than doubled following World War II. The distribution network has continued to expand to provide natural gas service to new commercial facilities and housing developments.

2 Sep 2025

Air Facility System Sites

This layer displays the locations of regulated facilities that discharge air pollutants in the United States. The Air Facility System (AFS) contains compliance and permit data for stationary sources of air pollution (such as electric power plants, steel mills, factories, and universities) regulated by EPA, state and local air pollution agencies. The information in AFS is used by the states to prepare State Implementation Plans (SIPs) and to track the compliance status of point sources with various regulatory programs under Clean Air Act. For more information, please visit the EPA Air Facility System web page.

2 Sep 2025

Oil and Natural Gas Fields

The layer represents Oil and Natural Gas Fields. Generally, Oil and Natural Gas “Fields” are defined as “a low in the Earth’s crust of tectonic origin in which sediments have accumulated.” This definition was originally defined by the Bureau of Land Management (BLM). Within the larger area of the basins this feature class also contains smaller geographic “plays” which are defined as “A set of known or postulated oil and gas accumulations sharing similar geologic, geographic, and temporal properties, such as source rock, migration, pathway, timing, trapping mechanism, and hydrocarbon type. A play differs from a basin; a basin can include one or more plays.” This definition was originally defined by the United States Geologic Survey (USGS) and was appropriated for use in the creation of this feature class. The geographic coverage of this layer is the Continental United States, Canada, and Mexico.

2 Sep 2025

Air Quality System Sites

This layer displays the locations of air quality monitoring stations in the United States. The Air Quality System (AQS) contains ambient air pollution data collected by EPA, state, Local, and tribal air pollution control agencies from thousands of monitoring stations. AQS also contains meteorological data, descriptive information about each monitoring station (including its geographic location and its operator), and data quality assurance/quality control information. For more information, please visit the EPA Air Quality System web page.

2 Sep 2025

Electric Bulk Power Transmission Lines

This layer represents electric power transmission lines. Transmission Lines are the system of structures, wires, insulators and associated hardware that carry electric energy from one point to another in an electric power system. Lines are operated at relatively high voltages varying from 69 kV up to 765 kV, and are capable of transmitting large quantities of electricity over long distances. Underground transmission lines are included where sources were available.

2 Sep 2025

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.).

2 Sep 2025

Watershed Boundary Dataset, 4-Digit Hydrologic Units

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.).

2 Sep 2025

Location Affordability Index for Family at AMI

This layer displays the estimated percentage of household income for housing and transportation for a family earning the Area Median Income (AMI). The expected values for housing and transportation are modeled by HUD using data from the US Census Bureau and the US Department of Transportation, including:

  • The average household size for a family earning AMI in the neighborhood
  • The average number of workers, vehicles, and vehicle miles traveled for a family in the neighborhood
  • The average utility and rental costs or average utility and mortgage costs for a housing unit to accommodate the family size above
  • The proportion of housing units that are either rentals or owner-occupied in the neighborhood

Note: The LAI does not predict what families are actually paying to live in a particular area, but rather what a family would pay (either in USD or as a percentage of income) if average or reasonable housing and commuting conditions for a particular neighborhood were achieved.

2 Sep 2025

Drought Severity, 2017-2019

This layer displays the percentage of weeks in Any Drought based on analysis of US Drought Monitor weekly drought data files for years 2017-2019.

2 Sep 2025

Location Affordability Index for Family Below AMI

This layer displays the estimated monthly cost for housing and transportation for a low-income, single-parent family (earning 50% of the Area Median Income). The values for housing and transportation are modeled by HUD using data from the US Census Bureau and the US Department of Transportation, including:

  • The average household size for a single-parent family earning 50% AMI in the neighborhood
  • The average number of workers, vehicles, and vehicle miles traveled for a family in the neighborhood
  • The average utility and rental costs or average utility and mortgage costs for a housing unit to accommodate the family size above
  • The proportion of housing units that are either rentals or owner-occupied in the neighborhood

Note: The LAI does not predict what families earning 50% AMI are actually paying to live in a particular area, but rather what a family would pay (either in USD or as a percentage of income) if average or reasonable housing and commuting conditions for a particular neighborhood were achieved.