Interstate Highway System Profiles

The United States Interstate Highway System is the world's second longest, with a total length of 47,856 miles as of 2013. It was authorized by the Federal Aid Highway Act of 1956, championed by Dwight D. Eisenhower, who it is named for. They were originally built for better military transportation and defense.


Interchanges: 14,750
Bridges: 55,512 (2005)
Most Traveled Interstate: I-405 in Los Angeles, California (374,000 vehicles per day, 2008 estimate)
Highest Elevation: 11,158 feet (I-70, Eisenhower Tunnel in Colorado)
Lowest Land Elevation: -52 feet (I-8, Seeley, California)
Lowest Underwater Elevation: -103 feet (I-95, Fort McHenry Tunnel in Baltimore, Maryland)

Longest Interstate Routes
 Interstate Terminus 1 Terminus 2 Length
I-90 Seattle, Washington Boston, Massachusetts  3,020 miles
 I-80  San Francisco, CaliforniaTeaneck, New Jersey  2,899 miles
 I-40 Barstow, CaliforniaWilmington, North Carolina  2,555 miles
I-10  Los Angeles, California Jacksonville, Florida 2,460 miles
 I-70 Cove Fort, UtahBaltimore, Maryland 2,153 miles 
Shortest 2-Digit Interstate Routes
Interstate Terminus 1 Terminus 2 Length
 I-97 Annapolis, Maryland Baltimore, Maryland17.6 miles 
I-99 Bedford, Pennsylvania  Bald Eagle, Pennsylvania53 miles 
I-73  Emery, North CarolinaGreensboro, North Carolina 56.7 miles 
 I-19Nogales, Arizona  Tuscon, Arizona 63.3 miles
 I-66Strasburg, Virginia  Washington, D.C. 74.8 miles
Interstate Routes Which Go Through the Most States
InterstateStates # of States
I-95 FL, GA, SC, NC, VA, DC, MD, DE, PA, NJ, NY, CT, RI, MA, NH, ME 16 states 
 I-90WA, ID, MT, WY, SD, MN, WI, IL, IN, OH, PA, NY, MA  13 states
I-80  CA, NV, UT, WY, NE, IA, IL, IN, OH, PA, NJ 11 states
 I-70 UT, CO, KS, MO, IL, IN, OH, WV, PA, MD 10 states
 I-10 CA, AZ, NM, TX, LA, MS, AL, FL 8 states
States with the most Interstate Routes
 State Miles Number of Routes
 New York 1,674 miles29 routes 
 California 2,455 miles25 routes 
 Illinois2,169 miles  23 routes
 Pennsylvania 1,759 miles 22 routes
 Ohio 1,572 miles 21 routes


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