List of suffixed Interstate Highways

In the United States, there are currently seven routes in the Interstate Highway System that are signed with letter suffixes to the route number. Interstate 35 (I-35) splits into I-35E and I-35W in the Dallas–Fort Worth metroplex in Texas, and similarly splits into I-35E and I-35W in the Minneapolis–St. Paul area in Minnesota. Other suffixed Interstates include I-69C, I-69E and I-69W in South Texas, and I-480N in Ohio, which is designated as such on mile markers but is otherwise unsigned. The state of Maryland has several unsigned suffixed Interstate designations that are designated by the Maryland State Highway Administration, rather than by the Federal Highway Administration (FHWA).

Dwight D. Eisenhower National System of Interstate and Defense Highways
Interstate 35E markerInterstate 69C marker
Highway shields for Interstate 35E and Interstate 69C
The 1958 Interstate Highway System plan included many suffixed Interstates.
System information
FormedJune 29, 1956[1]
Highway names
InterstatesInterstate X (I-X)
System links

There were once many more suffixed Interstates, as the three-digit Interstates were not designated until after all major routes were assigned numbers, including some short connections and spurs. (A few of the shortest, including I-190 and I-195, were assigned three-digit numbers almost immediately.) Most were not equal splits like on I-35, but had the main route continue through, and often the suffixed route never returned to its parent. In 1980, the American Association of State Highway and Transportation Officials (AASHTO) abolished the majority of suffixes due to confusion, renumbering them as three-digit Interstates. For example, I-15E in California has since become I-215.



Number Length (mi) Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
I-5W I-5 in Tracy, CA I-5 in Dunnigan, CA Replaced by I-580, I-80 and I-505
I-5E I-5 in Tracy, CA I-5 in Dunnigan, CA 1958 1982 Replaced by I-5
I-15E I-15 in Temecula, CA I-15 in Devore, CA 1973 1982 Renumbered from I-215 in 1973 and back to I-215 in 1982
I-15W I-15 in Murrieta, CA I-15 in San Bernardino, CA 1957 Became I-15 in 1957
I-15W I-80N in Rupert, ID I-15 in Pocatello, ID 1958 1980 Became I-86 in 1980; was also planned as I-82N
I-24W I-55 in Hayti, MO I-40 in Jackson, TN 1964 Did not connect to I-24; renumbered I-155
I-35W 85.20 137.12 I-35 in Hillsboro, TX I-35 in Denton, TX 1959 current
I-35E 96.76 155.72 I-35 in Hillsboro, TX I-35 in Denton, TX 1959 current
I-35W I-35 in Wichita, KS I-70 in Salina, Kansas 1976[2] Renumbered I-135[2]
I-35W 41.78 67.24 I-35 in Burnsville, MN I-35 in Forest Lake, MN
I-35E 39.34 63.31 I-35 in Burnsville, MN I-35 in Forest Lake, MN
I-59B Bypass for I-59 around Birmingham, AL Renumbered I-459
I-69W 1.43 2.30 Fed. 85D at Mexican border on World Trade International Bridge at Laredo, TX I-35/US 83/US 59/Loop 20 in Laredo, TX 2014 current
I-69C 18.02 29.00 I-2/US 83/US 281 in Pharr, TX US 281/Bus. US 281 near Edinburg, TX 2013 current
I-69E 53.31 85.79 East Rio Grande Valley segment: US 77/US 83/University Boulevard in Brownsville, TX
Corpus Christi area segment: US 77/SH 44 in Robstown, TX
East Rio Grande Valley segment: US 77/Bus. US 77 near Raymondville, TX
Corpus Christi area segment: I-37/US 77 in Corpus Christi, TX
2011 current
I-70S I-70 in Washington, PA I-70/I-80S in New Stanton, PA 1958 1964 Became part of I-70 and former I-70 became parts of I-79 and I-76
I-70N I-70 in Frederick, MD I-83/I-95 in Baltimore, MD 1958 1973 Became I-70
I-70S I-70 in Frederick, MD I-66/I-95 in Washington, DC 1958 1973 Became I-270
I-75E Bypass for I-75 around Tampa-St. Petersburg, FL 1973 Renumbered I-275; later swapped with I-75 in 1973
I-80N I-5 in Portland, OR I-80 in Echo, UT 1958 1980 Became I-84
I-80S I-25/I-70 in Denver, CO I-80 in Big Springs, NE 1958 1980 Became I-76
I-80N I-80 in Neola, IA I-29 in Loveland, IA 1973 Became part of I-680
I-80N I-80/I-90 in Lorain County, OH I-80S/SR 5 in Braceville Township, OH 1960 1962 Redesignated as I-80
I-80S I-80 in Youngstown, OH I-295 in Camden, NJ 1970 Extended west to Lodi, OH, by 1962 over former I-80; east end truncated to Monroeville, PA, and the part east of Monroeville renumbered I-76 in 1964; the rest became part of I-76
I-81S I-81 in Scranton, PA I-80 at Crescent Lake 1964 Formerly I-82, became I-81E (now I-380)
I-81E I-81 in Scranton, PA I-80 in Scotrun, PA 1964 1973 Formerly I-81S, became I-380
I-82S Burley, ID Tremonton, UT 1957 Became I-84
I-82N Burley, ID Pocatello, ID 1957 Became I-86
I-90N Buffalo, NY Canadian border at Lewiston, NY 1957 1959 Original designation for I-190 in New York, renamed I-190
I-94N Muskegon, MI I-94 in Grand Rapids, MI 1957 1959 Became I-196 in 1959[3] and then I-96 in 1964[4]
I-180N I-80N Boise, ID 1980 This was the only suffixed three-digit Interstate (until I-480N in Ohio was designated); all other spurs of suffixed routes had no suffix; became I-184
I-270 Spur 2.10[5] 3.38 I-270 in Bethesda, MD I-495 in Bethesda, MD 1975 current Signed as I-270 Spur; designated internally by MDSHA as I-270Y.
I-480N 1.99[6] 3.20 I-480 in Maple Heights, OH US 422 in Warrensville Heights, OH 1974 current Signed as I-480 on guide signs and reassurance markers, signed as I-480N on mile markers
I-495X 1.50[5] 2.41 I-495 in Bethesda, MD Clara Barton Parkway in Cabin John, MD 1965 current Also known as Cabin John Parkway; designated internally by MDSHA as I-495X; unsigned; trucks are not allowed on the length of the freeway
I-895A 0.71[5] 1.14 I-895B in Brooklyn Park, MD I-97 in Ferndale, MD 1965 current Unsigned. Internally designated by MDSHA as I-895A
I-895B 2.67[5] 4.30 I-895 in Brooklyn Park, MD Governor Ritchie Highway in Glen Burnie, MD 1965 current Unsigned. Internally designated by MDSHA as I-895B
  •       Former

See also

  • Blank shield.svg U.S. Roads portal


  1. ^ Weingroff, Richard F. (Summer 1996). "Federal-Aid Highway Act of 1956, Creating the Interstate System" . Public Roads. Washington, DC: Federal Highway Administration. 60 (1). Retrieved March 16, 2012.
  2. ^ a b Kansas Department of Transportation (2009). "1970s" . Kansas Celebrates 50 Years of Interstates. Kansas Department of Transportation. Archived from the original on February 12, 2012. Retrieved July 16, 2013.
  3. ^ "Spring to Bring Debut for Interstate Road Numbering" . The Herald-Press. St. Joseph, Michigan. Associated Press. January 8, 1959. p. 5. OCLC 10117184 . Retrieved July 11, 2018 – via
  4. ^ "Route Number Changes Slated" . Lansing State Journal. December 12, 1963. p. 10. OCLC 61312043 . Retrieved September 17, 2017 – via
  5. ^ a b c d Highway Information Services Division (December 2013). "Highway Location Reference" (Webpage). Maryland Department of Transportation.
  6. ^ Office of Technical Services (January 1999). "Technical Services Straight Line Diagram for I-480N" (PDF). Ohio Department of Transportation.

External links


Information as of: 16.08.2021 12:40:51 CEST

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