List of suffixed Interstate Highways

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
Formed:	June 29, 1956[1]
Highway names
Interstates:	Interstate X (I-X)
System links
Interstate Highway System Main Auxiliary Suffixed Business

Currently the Interstate Highway System includes seven suffixed routes that are signed: 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; as well as Interstate 69C, Interstate 69E and Interstate 69W in South Texas; in addition, 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.

List of suffixed Interstates

This list is incomplete; you can help by expanding it.

Number	Length (mi)	Length (km)	Southern or western terminus	Northern or eastern terminus	Formed	Removed	Notes
I-5W	—	—	I-5 in Tracy, California	I-5 in Dunnigan, California	—	—	Replaced by I-580, I-80 and I-505
I-5E	—	—	I-5 in Tracy, California	I-5 in Dunnigan, California	1958	1982	Replaced by I-5
I-15E	—	—	I-15 in Temecula, California	I-15 in Devore, California	1973	1982	Renumbered from I-215 in 1973 and back to I-215 in 1982
I-15W	—	—	I-15 in Pocatello, Idaho	I-80N in Rupert, Idaho	1958	—	became I-86 in 1980; Was also planned as Interstate 82N
I‑24W	—	—	I-40 in Jackson, Tennessee	I-55 in Hayti, Missouri	—	1964	Did not connect to I-24; renumbered I-155
I-35W	85.20	137.12	I-35 in Hillsboro, Texas	I-35 in Denton, Texas	—	—
I-35E	96.76	155.72	I-35 in Hillsboro, Texas	I-35 in Denton, Texas	—	—
I-35W	—	—	I-35 in Wichita, Kansas	I-70 in Salina, Kansas	—	1976[2]	Renumbered I-135[2]
I-35W	41.78	67.24	I-35 in Burnsville, Minnesota	I-35 in Forest Lake, Minnesota	—	—
I-35E	39.34	63.31	I-35 in Burnsville, Minnesota	I-35 in Forest Lake, Minnesota	—	—
I‑59B	—	—	Bypass for I-59 around Birmingham, Alabama		—	—	Renumbered I-459
I-69W	1.43	2.30	Fed. 85D at Mexican border on World Trade International Bridge in Laredo	I-35 / US 83 / US 59 / Loop 20 in Laredo	2014	current
I-69C	18.02	29.00	I-2 / US 83 / US 281 in Pharr	US 281 / Bus. US 281 near Edinburg	2013	current
I-69E	53.31	85.79	East Rio Grande Valley segment: US 77 / US 83 in Brownsville; Corpus Christi area segment: US 77 / SH 44 in Robstown	East Rio Grande Valley segment: US 77 / Bus. US 77 near Raymondville; Corpus Christi area segment: I-37 / US 77 in Corpus Christi	2011	current
I-70S	—	—	I-70 in Washington, Pennsylvania	I-70/I-80S in New Stanton, Pennsylvania	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, Maryland	I-83/I-95 in Baltimore, Maryland	1958	1973
I-70S	—	—	I-70 in Frederick, Maryland	I-66/I-95 in Washington, DC	1958	1973
I-75E	—	—	Bypass for I-75 around Tampa-St. Petersburg, Florida		—	1973	Renumbered I-275; later swapped with I-75 in 1980
I‑80N	—	—	I-80 in Echo, Utah	I-5 in Portland, Oregon	1958	1980	Became I-84
I‑80S	—	—	I-25/I-70 in Denver, Colorado	I-80 in Big Springs, Nebraska	1958	1980	became I-76
I‑80N	—	—	I-80 in Neola, Iowa	I-29 in Loveland, Iowa	—	1973	Became part of I-680
I‑80N	—	—	I-80/I-90 in Norwalk, Ohio	I-80 in Edinburg, Ohio	1958	1962
I‑80S	—	—	I-80 in Youngstown, Ohio	I-295 in Camden, New Jersey	—	1970	Extended west to Lodi, Ohio by 1962 over former I-80; east end truncated to Monroeville, Pennsylvania and the part east of Monroeville renumbered I-76 in 1964; the rest became part of I-76
I-81S	—	—	I-81 in Scranton, Pennsylvania	I-80 in Crescent Lake, Pennsylvania	—	1964	Formerly I-82, became I-81E (now I-380)
I-81E	—	—	I-81 in Scranton, Pennsylvania	I-80 in Scotrun, Pennsylvania	1964	1973	Formerly I-81S, became I-380
I‑82S	—	—	Burley, Idaho	Tremonton, Utah	1957	—	Became I-84
I-82N	—	—	Burley, Idaho	Pocatello, Idaho	1957	—	Became I-86
I-90N	—	—	Buffalo, New York	Canadian border at Lewiston, New York	—	1959	Original designation for I-190 in New York, renamed I-190
I-94N	—	—	Muskegon, Michigan	I-94 in Grand Rapids, Michigan	1957	1959
I-180N	—	—	I-80N	Boise, Idaho	—	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‑480N	1.99[3]	3.20	I-480 in Maple Heights	US 422 in Warrensville Heights	—	—	Unsigned on guide signs or reassurance markers, although it is signed on mile markers
Former

References

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. "1970s". Kansas Celebrates 50 Years of Interstates. Kansas Department of Transportation. Retrieved 2013-07-16.
3. Ohio Department of Transportation. "Technical Services Straight Line Diagram for I-480N" (PDF). Ohio Department of Transportation.

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