List of suffixed Interstate Highways

In the United States, there are currently seven "suffixed" Interstate Highways. In addition to the Interstate 35 split into Interstate 35E and Interstate 35W at Dallas-Fort Worth, Texas, a similar split into Interstate 35E and Interstate 35W at Minneapolis–St. Paul, Minnesota, exists, as well as Interstate 69C, Interstate 69E and Interstate 69W in South Texas. Interstate 480N in Ohio exists and is designated as such on mile markers but is otherwise unsigned. However, there were once many more, 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, AASHTO abolished the majority of suffixes due to confusion, renumbering them as three-digit Interstates, but several that return to their parents were kept. For example, Interstate 15E has since become Interstate 215, but both I-35E/I-35W and I-69 splits still exist, the I-69 splits being recently designated.

Dwight D. Eisenhower National System of Interstate and Defense Highways
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


Number Length (mi) Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
I-5W I-5 in Tracy, CAI-5 in Dunnigan, CA Replaced by I-580, I-80 and I-505
I-5E I-5 in Tracy, CAI-5 in Dunnigan, CA 01958-01-01195801982-01-011982 Replaced by I-5
I-15E I-15 in Temecula, CAI-15 in Devore, CA 01973-01-01197301982-01-011982 Renumbered from I-215 in 1973 and back to I-215 in 1982
I-15W I-15 in Murrieta, CAI-15 in San Bernardino, CA 01957-01-011957 Became I-15 in 1957
I-15W I-80N in Rupert, IDI-15 in Pocatello, ID 01958-01-01195801980-01-011980 Became I-86 in 1980; was also planned as I-82N
I-24W I-55 in Hayti, MOI-40 in Jackson, TN 01964-01-011964 Did not connect to I-24; renumbered I-155
I-35W 85.20137.12 I-35 in Hillsboro, TXI-35 in Denton, TX 01959-01-011959current
I-35E 96.76155.72 I-35 in Hillsboro, TXI-35 in Denton, TX 01959-01-011959current
I-35W I-35 in Wichita, KSI-70 in Salina, Kansas 01976-01-011976[2] Renumbered I-135[2]
I-35W 41.7867.24 I-35 in Burnsville, MNI-35 in Forest Lake, MN
I-35E 39.3463.31 I-35 in Burnsville, MNI-35 in Forest Lake, MN
I-59B Bypass for I-59 around Birmingham, AL Renumbered I-459
I-69W 1.432.30 Fed. 85D at Mexican border on World Trade International Bridge at Laredo, TXI-35/US 83/US 59/Loop 20 in Laredo, TX 02014-01-012014current
I-69C 18.0229.00 I-2/US 83/US 281 in Pharr, TXUS 281/Bus. US 281 near Edinburg, TX 02013-01-012013current
I-69E 53.3185.79 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
I-70S I-70 in Washington, PAI-70/I-80S in New Stanton, PA 01958-01-01195801964-01-011964 Became part of I-70 and former I-70 became parts of I-79 and I-76
I-70N I-70 in Frederick, MDI-83/I-95 in Baltimore, MD 01958-01-01195801973-01-011973 Became I-70
I-70S I-70 in Frederick, MDI-66/I-95 in Washington, DC 01958-01-01195801973-01-011973 Became I-270
I-75E Bypass for I-75 around Tampa-St. Petersburg, FL 01973-01-011973 Renumbered I-275; later swapped with I-75 in 1973
I-80N I-5 in Portland, ORI-80 in Echo, UT 01958-01-01195801980-01-011980 Became I-84
I-80S I-25/I-70 in Denver, COI-80 in Big Springs, NE 01958-01-01195801980-01-011980 Became I-76
I-80N I-80 in Neola, IAI-29 in Loveland, IA 01973-01-011973 Became part of I-680
I-80N I-80/I-90 in Lorain County, OHI-80S/SR 5 in Braceville Township, OH 01960-01-01196001962-01-011962 Redesignated as I-80
I-80S I-80 in Youngstown, OHI-295 in Camden, NJ 01970-01-011970 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, PAI-80 in Crescent Lake, PA 01964-01-011964 Formerly I-82, became I-81E (now I-380)
I-81E I-81 in Scranton, PAI-80 in Scotrun, PA 01964-01-01196401973-01-011973 Formerly I-81S, became I-380
I-82S Burley, IDTremonton, UT 01957-01-011957 Became I-84
I-82N Burley, IDPocatello, ID 01957-01-011957 Became I-86
I-90N Buffalo, NYCanadian border at Lewiston, NY 01957-01-01195701959-01-011959 Original designation for I-190 in New York, renamed I-190
I-94N Muskegon, MII-94 in Grand Rapids, MI 01957-01-01195701959-01-011959 Became I-196 in 1959[3] and then I-96 in 1964[4]
I-180N I-80NBoise, ID 01980-01-011980 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-480N 1.99[5]3.20 I-480 in Maple Heights, OHUS 422 in Warrensville Heights, OH 01974-01-011974current Signed as I-480 on guide signs and reassurance markers, signed as I-480N on mile markers
I-495X 1.50[6]2.41 I-495 in Bethesda, MDClara Barton Parkway in Cabin John, MD 01965-01-011965current Also known as Cabin John Parkway; designated internally by MDSHA as I-495X; unsigned; trucks are not allowed on the length of the freeway
  •       Former


  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. 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.
  4. "Route Number Changes Slated". Lansing State Journal. December 12, 1963. p. 10. OCLC 61312043. Retrieved September 17, 2017 via
  5. Office of Technical Services (January 1999). "Technical Services Straight Line Diagram for I-480N" (PDF). Ohio Department of Transportation.
  6. Highway Information Services Division (December 2013). "Highway Location Reference" (Webpage). Maryland Department of Transportation.
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