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List of Interstate Highways facts for kids

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Interstate 90 marker Eisenhower Interstate System sign
Highway shield for Interstate 90 and the Eisenhower Interstate System
Quick facts for kids
System information
Formed: June 29, 1956
Highway names
Interstates: Interstate X (I-X)
System links

There are 70 primary Interstate Highways in the Interstate Highway System, a network of freeways in the United States. These primary highways are assigned one- or two-digit route numbers, whereas their associated auxiliary Interstate Highways receive three-digit route numbers. Typically, odd-numbered Interstates run south–north, with lower numbers in the west and higher numbers in the east; even-numbered Interstates run west–east, with lower numbers in the south and higher numbers in the north. Route numbers divisible by 5 usually represent major coast-to-coast or border-to-border routes (ex. I-10 connects Santa Monica, California to Jacksonville, Florida, extending between the Pacific and Atlantic oceans). Auxiliary highways have an added digit prefixing the number of the parent highway.

Five route numbers are duplicated in the system; the corresponding highways are in different regions, reducing potential confusion. In addition to primary highways in the contiguous United States, there are signed Interstates in Hawaii and unsigned Interstates in Alaska and Puerto Rico.

Contiguous United States

There are 70 primary interstate highways in the 48 contiguous United States as well as five former and one future primary interstate highways. This number does not include auxiliary Interstate Highways.

Number Length (mi) Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
I-2 46.80 75.32 BL US 83 in Peñitas, Texas I-69E/US 77/US 83 in Harlingen, Texas 2013 current Unfinished in Texas
Texas only
I-4 132.30 212.92 I-275 in Tampa, Florida I-95/SR 400 in Daytona Beach, Florida 1959 current Florida only
I-8 348.25 560.45 Sunset Cliffs Boulevard/Nimitz Boulevard in San Diego, California I-10 in Casa Grande, Arizona 1964 current Serves two states: California, Arizona
I-11 22.60 36.37 US 93 at Arizona state line near Boulder City, Nevada I-215/I-515/US 93/US 95/SR 564 in Henderson, Nevada 2017 current Unfinished in Nevada
Nevada only; planned in one more: Arizona
I-12 85.59 137.74 I-10 in Baton Rouge, Louisiana I-10/I-59 in Slidell, Louisiana 1967 current Louisiana only
I-14 25.10 40.39 US 190/US 190 Bus in Copperas Cove, Texas I-35/US 190 in Belton, Texas 2017 current Unfinished in Texas
Texas only; planned in four more: Louisiana, Mississippi, Alabama, Georgia
Planned associated routes: I-14N, I-14S, and I-214 in Texas
I-16 166.81 268.45 I-75/SR 540 in Macon, Georgia Montgomery Street in Savannah, Georgia 1966 current Georgia only
Associated route: I-516
I-17 145.76 234.58 I-10/US 60 in Phoenix, Arizona I-40/SR 89A in Flagstaff, Arizona 1961 current Arizona only
I-19 63.35 101.95 I-19 Bus. in Nogales, Arizona I-10 in Tucson, Arizona 1972 current Arizona only
Uses kilometers instead of miles
I-22 202.22 325.44 I-269/US 78/MS 304 near Byhalia, Mississippi I-65 in Birmingham, Alabama 2012 current Unfinished in Alabama
Serves two states: Mississippi, Alabama
Planned associated routes: I-222 and I-422 in Alabama
I-24 316.36 509.13 I-57 in Pulley's Mill, Illinois I-75 in Chattanooga, Tennessee 1962 current Serves four states: Illinois, Kentucky, Tennessee, Georgia
Associated route: I-124
I-25 1,061.67 1,708.59 I-10/US 85/US 180 in Las Cruces, New Mexico I-90/US 87 in Buffalo, Wyoming 1957 current Serves three states: New Mexico, Colorado, Wyoming
Associated route: I-225
I-26 304.64 490.27 US 11W/US 23/SR 137 in Kingsport, Tennessee US 17 in Charleston, South Carolina 1960 current Unfinished in North Carolina
Serves three states: Tennessee, North Carolina, South Carolina
Associated routes: I-126, I-526
I-27 124.13 199.77 US 87/Loop 289 in Lubbock, Texas I-40/US 87/US 287/US 60 in Amarillo, Texas 1969 current Unfinished in Texas
Texas only; planned in one more: New Mexico
I-30 366.76 590.24 I-20 in Fort Worth, Texas I-40/US 65/US 67/US 167 in North Little Rock, Arkansas 1957 current Serves two states: Texas, Arkansas
Associated routes: I-430, I-530, I-630
I-31 — — I-94 in Fargo, North Dakota US 81 and PTH 75 at Canadian border in Pembina, North Dakota 1957 1958 Served North Dakota only
Replaced by a northward extension of I-29
I-37 143.00 230.14 US 181 in Corpus Christi, Texas I-35/US 281 in San Antonio, Texas 1959 current Texas only
I-39 306.14 492.68 I-55 in Normal, Illinois WIS 29/US 51 in Wausau, Wisconsin 1984 current Serves two states: Illinois, Wisconsin
I-41 175.00 281.64 I-94/US 41 in Russell, Illinois I-43/US 41/US 141 in Howard, Wisconsin 2015 current Serves two states: Illinois, Wisconsin
I-42 142.00 228.53 I-40/US 70 in Garner, North Carolina US 70 in Morehead City, North Carolina proposed — Future Interstate, will only serve North Carolina
I-43 191.55 308.27 I-39/I-90 in Beloit, Wisconsin I-41/US 41/US 141 in Howard, Wisconsin 1981 current Wisconsin only
I-44 636.69 1,024.65 US 82/US 277/US 281/US 287 in Wichita Falls, Texas I-70 in St. Louis, Missouri 1958 current Serves three states: Texas, Oklahoma, Missouri
Associated routes: I-244, I-444; Future: I-344 in Oklahoma
I-45 284.91 458.52 SH 87 in Galveston, Texas I-30/US 67/US 75 in Dallas, Texas 1971 current Texas only
Associated route: I-345
I-49 528.02 849.77 I-10/US 167/LA 182 in Lafayette, Louisiana I-435/I-470/US 50/US 71 in Kansas City, Missouri 1984 current Unfinished in Arkansas and Louisiana
Serves three states: Louisiana, Arkansas, Missouri; planned in one more: Texas
I-57 386.12 621.40 I-55 in Miner, Missouri I-94 in Chicago, Illinois 1965 current Unfinished in Missouri
Serves two states: Missouri, Illinois; planned in one more: Arkansas
I-59 445.23 716.53 I-10/I-12 in Slidell, Louisiana I-24 in Wildwood, Georgia 1960 current Serves four states: Louisiana, Mississippi, Alabama, Georgia
Associated routes: I-359, I-459, I-759
I-66 — — Witchita, Kansas Near Pikeville, Kentucky 1991 2015 Served four states: Kansas, Missouri, Illinois, Kentucky
Associated routes: I-66 Spur in Kentucky
The project was unpopular and ultimately cancelled without the interstate being completed; I-66 Spur eventually became I-165
I-66 76.28 122.76 I-81 in Front Royal, Virginia US 29 in Washington, D.C. 1961 current Serves DC and one state: Virginia
I-68 113.15 182.10 I-79 in Morgantown, West Virginia I-70 in Hancock, Maryland 1991 current Serves two states: West Virginia, Maryland
I-71 345.57 556.14 I-64 in Louisville, Kentucky I-90 in Cleveland, Ohio 1959 current Serves two states: Kentucky, Ohio
Associated routes: I-271, I-471
I-72 179.29 288.54 US 61 in Hannibal, Missouri Church Street and University Avenue in Champaign, Illinois 1970 current Serves two states: Missouri, Illinois
Associated route: I-172
I-73 99.43 160.02 US 220 near Stokesdale, North Carolina I‑74 and US 220 in Randleman, North Carolina 1997 current Unfinished in North Carolina
North Carolina only; planned in five more: South Carolina, Virginia, West Virginia, Ohio, Michigan
I-74 491.74 791.38 I-80 in Bettendorf, Iowa US 74/NC 41 near Lumberton, North Carolina 1974 current Unfinished in Ohio and North Carolina
Serves five states: Iowa, Illinois, Indiana, Ohio, North Carolina; planned in three more: West Virginia, Virginia, South Carolina
Associated routes: I-474; Planned: I-274 in North Carolina
I-76 186.48 300.11 I-70 at Denver, Colorado I-80 at Big Springs, Nebraska 1975 current Serves two states: Colorado, Nebraska
I-76 435.66 701.13 I-71 in Westfield Center, Ohio I-295 at Bellmawr, New Jersey 1964 current Serves three states: Ohio, Pennsylvania, New Jersey
Associated routes: I-176, I-276, I-376, I-476, I-676
I-78 146.28 235.41 I-81 at Jonestown, Pennsylvania Canal Street in New York City 1957 current Serves three states: Pennsylvania, New Jersey, New York
Associated routes: I-278, I-478, I-678, I-878
I-79 343.46 552.75 I-77 in Charleston, West Virginia PA 5 in Erie, Pennsylvania 1967 current Serves two states: West Virginia, Pennsylvania
Associated routes: I-279, I-579
I-81 855.02 1,376.02 I-40 in Dandridge, Tennessee Hwy 137 at Canadian border on Wellesley Island, New York 1961 current Serves six states: Tennessee, Virginia, West Virginia, Maryland, Pennsylvania, New York
Associated routes: I-381, I-481, I-581, I-781
I-82 143.58 231.07 I-90 in Ellensburg, Washington I-84 in Hermiston, Oregon 1957 current Serves two states: Washington, Oregon
Associated route: I-182
I-82 — — I-81/I-84/US 6 in Scranton, Pennsylvania I-95 in Teaneck, New Jersey 1957 1958 Served two states: Pennsylvania, New Jersey
Was the initial designation to what is now I-380 and I-80
I-82 — — I-84 in East Hartford, Connecticut Providence, Rhode Island 1956 1968 Served one state: Connecticut, was planned for one state: Rhode Island
Redesignated as I-84 in 1968
I-83 85.03 136.84 President Street and Fayette Street in Baltimore, Maryland I-81 in Harrisburg, Pennsylvania 1959 current Serves two states: Maryland, Pennsylvania
Associated route: I-283
I-84 769.62 1,238.58 I-5 in Portland, Oregon I-80 in Echo, Utah 1980 current Serves three states: Oregon, Idaho, Utah
Associated route: I-184
I-84 232.71 374.51 I-81 in Scranton, Pennsylvania I-90 in Sturbridge, Massachusetts 1963 current Serves four states: Pennsylvania, New York, Connecticut, Massachusetts
Associated routes: I-384, I-684
I-86 62.85 101.15 I-84 near Declo, Idaho I-15 in Chubbuck, Idaho 1980 current Idaho only
I-86 223.39 359.51 I-90 near North East, Pennsylvania NY 17/NY 79 in Windsor, New York 1999 current Unfinished in New York
Serves two states: Pennsylvania, New York
I-86 38.97 62.72 I-84 in East Hartford, Connecticut I-90 in Sturbridge, Massachusetts 1968 1984 Served two states: Connecticut, Massachusetts
Redesignated as I-84 in 1984 when the I-84 Hartford-Providence corridor was cancelled
I-87 12.90 20.76 I-440/US 64/US 264 in Raleigh, North Carolina US 64/US 264 in Wendell, North Carolina 2017 current Unfinished in North Carolina
North Carolina only; planned in one more: Virginia
Associated route: I-587
Shortest Interstate highway in contiguous United States
I-87 333.49 536.70 I-278 in New York City A-15 at Canadian border in Champlain, New York 1957 current New York only
Associated routes: I-287, I-587, I-787
I-88 140.60 226.27 I-80/IL 92 in East Moline, Illinois I-290/IL 110 in Hillside, Illinois 1987 current Illinois only
I-88 117.75 189.50 I-81 in Binghamton, New York I-90 in Schenectady, New York 1968 current New York only
I-89 191.12 307.58 I-93/SR 3A in Bow, New Hampshire Route 133/Future A-35 at Canadian border in Highgate, Vermont 1960 current Serves two states: New Hampshire, Vermont
Associated route: I-189
I-93 189.95 305.69 I-95/US 1 in Canton, Massachusetts I-91 in St. Johnsbury, Vermont 1957 current Serves three states: Massachusetts, New Hampshire, Vermont
Associated routes: I-293, I-393
I-96 192.06 309.09 US 31 in Norton Shores, Michigan I-75 in Detroit, Michigan 1959 current Michigan only
Associated routes: I-196, I-296, I-496, I-696
I-97 17.62 28.36 US 50 in Annapolis, Maryland I-695/I-895 in Glen Burnie, Maryland 1987 current Maryland only
I-99 98.34 158.26 I-70/I-76 in Bedford, Pennsylvania I-86/NY 17 in Painted Post, New York 1998 current Unfinished in Pennsylvania
Serves two states: Pennsylvania, New York
  •       Former
  •       Future

Other regions

In addition to the 48 contiguous states, Interstate Highways are found in Hawaii, Alaska, and Puerto Rico. The Federal Highway Administration funds four routes in Alaska and three routes in Puerto Rico under the same program as the rest of the Interstate Highway System. However, these routes are not required to meet the same standards as the mainland routes:

Highways on the Interstate System in Alaska and Puerto Rico shall be designed in accordance with such geometric and construction standards as are adequate for current and probable future traffic demands and the needs of the locality of the highway.

Hawaii

The Interstate Highways on the island of Oʻahu, Hawaii are signed with the standard Interstate Highway shield, with the letter "H-" prefixed before the number. They are fully controlled-access routes built to the same standards as the mainland Interstate Highways.

Number Length (mi) Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
H-1 27.16 43.71 Route 93 in Kapolei Route 72 in Honolulu 1960 current Associated route: H-201
H-2 8.33 13.41 H-1 in Pearl City Route 99 in Wahiawa 1960 current
H-3 15.32 24.66 H-1/H-201 in Halawa Marine Corps Base Hawaii 1997 current

Alaska

Main page: List of Interstate Highways in Alaska

Alaska's Interstate Highways are unsigned as such, although they all have state highway numbers that do not match the Interstate Highway numbers.

Number Length (mi) Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
A‑1 408.23 656.98 Anchorage Canadian border in Alcan Border 1976 current Glenn Highway, Richardson Highway, Tok Cut-Off, Alaska Highway
A‑2 202.18 325.38 Tok Fairbanks 1976 current Alaska Highway, Richardson Highway
A‑3 148.12 238.38 Anchorage Soldotna 1976 current Seward Highway, Sterling Highway
A‑4 323.69 520.93 Gateway, near Palmer Fairbanks 1976 current Parks Highway

Puerto Rico

Main page: List of highways in Puerto Rico#Interstates
Puerto Rico Interstates
Map of the Interstates in Puerto Rico

Puerto Rico signs its Interstate Highways as territorial routes, as the numbers do not match their official Interstate Highway designations. Many of the territory's routes are freeway-standard toll roads.

Number Length (mi) Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
PR-1 71.08 114.39 PR-2 in Ponce PR-2 in San Juan 1976 current Follows PR-52
PR-2 138.13 222.30 PR-1 in Ponce PR-3 in San Juan 1976 current Follows PR-22
PR-3 40.56 65.27 PR-3 in Humacao PR-2 in San Juan 1976 current Follows PR-66

See also

Kids robot.svg In Spanish: Anexo:Autopistas Interestatales Primarias para niños

  • List of United States Numbered Highways
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