Data are for 2011 unless otherwise noted.

Transportation System Extent

All public roads: 4.08 million miles
Interstate: 46,960 miles
Road bridges: 605,103
Class I railroad trackage: 162,393 miles
Inland waterways: 29,620 miles
Public use airports: 5,172

Vehicles and Conveyances

Automobiles registered: 125.7 million
Trucks registered: 118.5 million
Buses registered: 0.7 million
Motorcycles registered: 8.4 million
Rail transit systems: 25 commuter rail, 14 heavy rail (subway), 30 light rail
Recreational boats registered: 12.2 million

Geographic

Land area: 3.5 million square miles¹
Percent of land area owned by federal government: 27.7¹
Persons per square mile: 87.4¹
Highest point: Mount McKinley, AK (20,320 ft.)
Lowest point: Death Valley, CA (–282 ft.)

Government Subdivisions

County governments: 3,033²
Municipal governments: 19,492²
Town governments: 16,519²
Congressional districts: 435

Demographic

Population: 311.6 million
Percent urban population: 82.0¹

Socioeconomic

Gross domestic product: $13.3 trillion in chained (2005) dollars ($15.1 trillion in current dollars)
Civilian labor force: 153.6 million
Median household income: $50,502

Commuting (percent of workers)

Car, truck, or van—drove alone: 76.4
Car, truck, or van—carpooled: 9.7
Public transportation: 5.0
Worked at home: 4.3
Walked: 2.8
Taxicab, motorcycle, bicycled or other means: 1.7

¹2010
²2007
 

Sources

Transportation System Extent
All public roads, Interstate: U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2011, table HM-20; available at www.fhwa.dot.gov/policyinformation/statistics.cfm as of June 2013.
Road bridges: U.S. Department of Transportation, Federal Highway Administration, Office of Bridge Technology, National Bridge Inventory, Highway Bridge by Owner, available at www.fhwa.dot.gov/bridge/britab.cfm as of June 2013.
Class I railroad trackage: Association of American Railroads, Class I Railroad Statistics available at www.aar.org/StatisticsAndPublications.aspx as of June 2013.
Inland waterways: U.S. Army Corps of Engineers, Navigation Data Center, National Waterway Network, personal communication, March 2013.
Public use airports: U.S. Department of Transportation, Federal Aviation Administration, Administrator’s Fact Book June 2012, p.16, available at www.faa.gov/about/office_org/headquarters_offices/aba/admin_factbook as of June 2013.

Vehicles and Conveyances
Automobiles, light trucks, heavy trucks, buses, motorcycles: U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2011, table MV-1, available at www.fhwa.dot.gov/policyinformation/statistics.cfm as of June 2013.
Rail transit systems: U.S. Department of Transportation, Federal Transit Agency, National Transit Database 2011, table 21, available at www.ntdprogram.gov/ntdprogram/data.htm as of June 2013.
Recreational boats: U.S. Department of Homeland Security, U.S. Coast Guard, Boating Statistics 2011, table 36, available at www.uscgboating.org/statistics/accident_statistics.aspx as of June 2013.

Geographic
Land area, persons per square mile: U.S. Department of Commerce, U.S. Census Bureau, USA QuickFacts, available at quickfacts.census.gov/qfd/states/00000.html as of June 2013.
Percent of federal land: Library of Congress, Congressional Research Service, Federal Land Ownership: Overview and Data, February 2012, R42346 as for June 2013.
Highest and lowest point: Central Intelligence Agency, The World Factbook, available at https://www.cia.gov/library/publications/the-world-factbook/geos/us.html as of June 2013.

Government Subdivisions
Governments: U.S. Department of Commerce, U.S. Census Bureau, 2007 Census of Governments, available at http://www.census.gov/govs/cog/ as of June 2013.
Districts: U.S. Department of Commerce, U.S. Census Bureau, 2010 Apportionment Results, available at www.census.gov/population/apportionment/data/ as of June 2013.

Demographic
Population: U.S. Department of Commerce, U.S. Census Bureau, Population Estimates, Vintage 2012, Annual Population Estimates available at www.census.gov/popest/ as of June 2013.
Percent urban population:  Central Intelligence Agency, The World Factbook, available at https://www.cia.gov/library/publications/the-world-factbook/geos/us.html as of June 2013.

Socioeconomic
Gross domestic product: U.S. Department of Commerce, Bureau of Economic Analysis, National Income and Product Account Tables, available at www.bea.gov/itable as of June 2013.
Civilian labor force: U.S. Department of Labor, Bureau of Labor Statistics, Labor Force Statistics from the Current Population Survey, available at www.bls.gov/cps as of June 2013.
Median household income: U.S. Census Bureau, 2011 American Community Survey, table S1903, available at factfinder.census.gov as of June 2013.

Commuting
U.S. Census Bureau, 2011 American Community Survey, table B08101 available at www.census.gov/acs as of June 2013.