Interstate Highway System Trivia
Facts and figures on the U.S. highway system
by Federal Highway Administration
 Related Links
External Links |
See also: The Story of the U.S. Interstate
Longest Interstate Routes | ||
| Interstate | From To | Miles |
| I-90 | Seattle, WA to Boston, MA | 3,020.54 miles |
| I-80 | San Francisco, CA to Teaneck, NJ | 2,899.54 miles |
| I-40 | Barstow, CA to Wilmington, NC | 2,555.40 miles |
| I-10 | Los Angeles, CA to Jacksonville, FL | 2,460.34 miles |
| I-70 | Cove Fort, UT to Baltimore, MD | 2,153.13 miles |
Shortest (2-Digit) Interstate Routes | ||
| Interstate | From To | Miles |
| I-97 | Annapolis to Baltimore, MD | 17.62 miles |
| I-99 | Bedford to Bald Eagle, PA | 53.00 miles* |
| I-73 | Emery to Greensboro, NC | 56.70 miles |
| I-19 | Nogales to Tucson, AZ | 63.35 miles |
| I-66 | Strasburg, VA to Washington, DC | 74.80 miles |
| (* Additional miles of I-73 in NC and I-99 in PA are expected to be built) | ||
East-West Transcontinental Routes | ||
| Interstate | From To | Miles |
| I-10 | Los Angeles, CA to Jacksonville, FL | 2,460.34 miles |
| I-80 | San Francisco, CA to Teaneck, NJ | 2,899.54 miles |
| I-90 | Seattle, WA to Boston, MA | 3,020.54 miles |
North-South Transcontinental Routes | ||
| Interstate | From To | Miles |
| I-5 | San Diego, CA to Blaine, WA | 1,381.29 miles |
| I-15 | San Diego, CA to Sweetgrass, MT | 1,433.52 miles |
| I-35 | Laredo, TX to Duluth, MN | 1,568.38 miles |
| I-55 | New Orleans, LA to Chicago, IL | 964.25 miles |
| I-65 | Mobile, AL to Gary, IN | 887.30 miles |
| I-75 | Miami, FL to Sault Ste Marie, MI | 1,786.47 miles |
| I-95 | Miami, FL to Houlton, ME | 1,919.74 miles |
States with Most Interstate Mileage | ||
| States | Number | Miles |
| Texas | 17 routes | 3,233.45 miles |
| California | 25 routes | 2,455.74 miles |
| Illinois | 23 routes | 2,169.53 miles |
| Pennsylvania | 22 routes | 1,759.34 miles |
| Ohio | 21 routes | 1,572.35 miles |
States with Most Interstate Routes | ||
| States | Number | Miles |
| New York | 1,674.73 miles | 29 routes |
| California | 2,455.74 miles | 25 routes |
| Illinois | 2,169.53 miles | 23 routes |
| Pennsylvania | 1,759.34 miles | 22 routes |
| Ohio | 1,572.35 miles | 21 routes |
Most Costly Routes (Eligible for Interstate Construction Funds Based on 1991 Cost Estimate) | ||
| Interstate | From To | Cost |
| I-95 | Miami, FL to Houlton, ME | $8.0 billion |
| I-90 | Seattle, WA to Boston, MA | $7.5 billion |
| I-75 | Miami, FL to Sault Ste Marie, MI | $5.1 billion |
| I-10 | Los Angeles, CA to Jacksonville, FL | $5.0 billion |
Interstate Routes Which Traverse the Most States | ||
| Interstate | States | Number |
| I-95 | FL, GA, SC, NC, VA, DC, MD, DE, PA, NJ, NY, CT, RI, MA, NH, ME | 16 States |
| I-90 | WA, 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 |
State Capitals
All but five State capitals are directly served by the Interstate System. Those not directly served are:
Juneau, AK
Dover, DE
Jefferson City, MO
Carson City, NV
Pierre, SD
Oldest Segments
The oldest Interstate segments actually predate the establishment of the Interstate system. Early examples include a portion of the Grand Central Parkway in Queens, New York, which was opened to traffic in July 1936 and later was incorporated into the Interstate System as I-278. The Pennsylvania Turnpike between Irwin (southeast of Pittsburgh) and Carlisle (west of Harrisburg) was officially opened in October 1940 and is now designated as I-76 and I-70. Other freeways and toll roads were incorporated into the System rather than build new competing Interstate routes.
Rest Areas
An exact count of rest areas on the Interstate System is not available. However, a count in 1972 reported 1,214 rest areas in existence. The number still operational today is not expected to differ dramatically from the 1972 figure.
Interchanges
An exact count of the number of interchanges on the Interstate System is not available. However, a 1978 count found 14,231 interchanges. This number has likely increased somewhat over the intervening years.
