Currently the Interstate Highway System

Interstate Highway System

The Dwight D. Eisenhower National System of Interstate and Defense Highways, , is a network of limited-access roads including freeways, highways, and expressways forming part of the National Highway System of the United States of America...

 includes four suffixed routes - the Interstate 35

Interstate 35

Interstate 35 is a north–south Interstate Highway in the central United States. I-35 stretches from Laredo, Texas, on the U.S.-Mexico border to Duluth, Minnesota, at Minnesota Highway 61 and 26th Avenue East. Many interstates used to have splits or spurs indicated with suffixed letters , but I-35...

 split into Interstate 35E

Interstate 35E (Texas)

Interstate 35E , an Interstate Highway, is the eastern half of Interstate 35 where it splits to serve different cities in Texas. I-35 splits into two branch routes, I-35W and I-35E at Hillsboro. I-35E runs north for , maintaining I-35's sequence of exit numbers. It runs through Dallas before...

 and Interstate 35W

Interstate 35W (Texas)

Interstate 35W , an Interstate Highway, is the western half of Interstate 35 where it splits to serve different cities in Texas. I-35 splits into two branch routes, I-35W and I-35E at Hillsboro. I-35W runs north for , carrying its own separate sequence of exit numbers. It runs through Fort Worth...

 at Dallas-Fort Worth, Texas and a similar split into Interstate 35E

Interstate 35E (Minnesota)

Interstate 35E is an Interstate Highway in the U.S. state of Minnesota, passing through downtown Saint Paul. It is one of two through routes for Interstate 35 through the Twin Cities of Minneapolis and Saint Paul, the other being Interstate 35W through Minneapolis. Thus, both ends of I-35E are...

 and Interstate 35W

Interstate 35W (Minnesota)

Interstate 35W , is an Interstate Highway in the U.S. state of Minnesota, passing through downtown Minneapolis. It is one of two through routes for Interstate 35 through the Twin Cities of Minneapolis and Saint Paul, the other being Interstate 35E through downtown Saint Paul...

 at Minneapolis-St. Paul, Minnesota. 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. Interstate 15E has since become Interstate 215

Interstate 215 (California)

Interstate 215 is a long north–south Interstate highway in the Inland Empire region of Southern California. It is an auxiliary route of Interstate 15 , running from Murrieta to northern San Bernardino...

, but both I-35E/I-35W splits still exist.

Current routes

Interstate	Extent
I-35W Interstate 35W (Texas) Interstate 35W , an Interstate Highway, is the western half of Interstate 35 where it splits to serve different cities in Texas. I-35 splits into two branch routes, I-35W and I-35E at Hillsboro. I-35W runs north for , carrying its own separate sequence of exit numbers. It runs through Fort Worth... I-35E Interstate 35E (Texas) Interstate 35E , an Interstate Highway, is the eastern half of Interstate 35 where it splits to serve different cities in Texas. I-35 splits into two branch routes, I-35W and I-35E at Hillsboro. I-35E runs north for , maintaining I-35's sequence of exit numbers. It runs through Dallas before...	Hillsboro, Texas Hillsboro, Texas Hillsboro is a city in and the county seat of Hill County in Central Texas. The population was 8,232 at the 2000 census.Hillsboro, located on Interstate 35 where I-35E and I-35W meet south of the Dallas-Fort Worth Metroplex, is the primary center for trade and commerce in Hill County...  (I-35) to Denton, Texas Denton, Texas The city of Denton is the county seat of Denton County, Texas in the United States. Its population was 119,454 according to the 2010 U.S. Census, making it the eleventh largest city in the Dallas/Fort Worth Metroplex...  (I-35)
I-35W Interstate 35W (Minnesota) Interstate 35W , is an Interstate Highway in the U.S. state of Minnesota, passing through downtown Minneapolis. It is one of two through routes for Interstate 35 through the Twin Cities of Minneapolis and Saint Paul, the other being Interstate 35E through downtown Saint Paul... I-35E Interstate 35E (Minnesota) Interstate 35E is an Interstate Highway in the U.S. state of Minnesota, passing through downtown Saint Paul. It is one of two through routes for Interstate 35 through the Twin Cities of Minneapolis and Saint Paul, the other being Interstate 35W through Minneapolis. Thus, both ends of I-35E are...	Burnsville, Minnesota Burnsville, Minnesota Burnsville is a city south of downtown Minneapolis in Dakota County in the U.S. state of Minnesota. The city lies on the south bank of the Minnesota River, upstream from the confluence with the Mississippi River...  (I-35) to Forest Lake, Minnesota Forest Lake, Minnesota Forest Lake is a city in Washington County, Minnesota, United States. The population was 18,375 at the 2010 census. It is located on Minnesota's 94th largest lake .Interstate 35 and U.S...  (I-35)

Former routes

Interstate	Extent	Notes
I-5W I-5E	Tracy, California Tracy, California Tracy is the second most populated city in San Joaquin County, California, United States and an exurb of the San Francisco Bay Area. The population was 82,922 at the 2010 census.-History:...  (I-5) to Dunnigan, California Dunnigan, California Dunnigan is a census-designated place in Yolo County, California on Interstate 5. The population was 1,416 at the 2010 census. Dunnigan's ZIP code is 95937 and its area code 530. It lies at an elevation of 69 feet .-History:...  (I-5)	In the 1958 plan; I-5E changed to I-5 and I-5W to I-580, I-80 and I-505 in 1964
I-15E	Temecula, California Temecula, California Temecula is a city in southwestern Riverside County, California, United States with a population of 100,097 according to the 2010 United States Census, making it the lowest populated American city over 100,000 population. It was incorporated on December 1, 1989...  (I-15) to Devore, California Devore, California Devore is a neighborhood in the city of San Bernardino, California. It is located near the northern junction of Interstate 15 and Interstate 215. The area is just outside the boundaries of the San Bernardino National Forest; nearby cities/town centers include Universitytown, Fontana, and Rialto...  (I-15)	Renumbered from I-215 in 1973 and back to I-215 in 1982
I-15W	Pocatello, Idaho Pocatello, Idaho Pocatello is the county seat and largest city of Bannock County, with a small portion on the Fort Hall Indian Reservation in neighboring Power County, in the southeastern part of the U.S. state of Idaho. It is the principal city of the Pocatello metropolitan area, which encompasses all of Bannock...  (I-15) to Rupert, Idaho Rupert, Idaho Rupert is the county seat and largest city of Minidoka County, Idaho, United States. It is part of the Burley, Idaho Micropolitan Statistical Area...  (I-80N)	In the 1958 plan; became I-86
I-24W	Jackson, Tennessee Jackson, Tennessee Jackson is a city in Madison County, Tennessee, United States. The total population was 65,211 at the 2010 census. Jackson is the primary city of the Jackson, Tennessee metropolitan area, which is included in the Jackson-Humboldt, Tennessee Combined Statistical Area...  (I-40) to Hayti, Missouri Hayti, Missouri Hayti is a city in Pemiscot County, Missouri, United States. The population was 3,207 at the 2000 census.In 1955, a small earthquake broke windows in the village.- Geography :Hayti is located at ....  (I-55)	Did not connect to I-24; renumbered I-155 in 1964
I-35W	Wichita, Kansas Wichita, Kansas Wichita is the largest city in the U.S. state of Kansas.As of the 2010 census, the city population was 382,368. Located in south-central Kansas on the Arkansas River, Wichita is the county seat of Sedgwick County and the principal city of the Wichita metropolitan area...  (I-35) to Salina, Kansas Salina, Kansas Salina is a city in and the county seat of Saline County, Kansas, United States. As of the 2010 census, the city population was 47,707. Located in one of the world's largest wheat-producing areas, Salina is a regional trade center for north-central Kansas...  (I-70)	In the 1958 plan; renumbered I-135 in 1980
I-59B	Bypass for I-59 around Birmingham, Alabama Birmingham, Alabama Birmingham is the largest city in Alabama. The city is the county seat of Jefferson County. According to the 2010 United States Census, Birmingham had a population of 212,237. The Birmingham-Hoover Metropolitan Area, in estimate by the U.S...	Renumbered I-459
I-70S	Washington, Pennsylvania Washington, Pennsylvania Washington is a city in and the county seat of Washington County, Pennsylvania, United States, within the Pittsburgh Metro Area in the southwestern part of the state...  (I-70) to New Stanton, Pennsylvania New Stanton, Pennsylvania New Stanton is a borough in Westmoreland County, Pennsylvania, United States. The population was 1,906 at the 2000 census. New Stanton is often used as a control city in western parts of Pennsylvania, as I-70 joins the Pennsylvania Turnpike eastbound towards Breezewood, Pennsylvania in New...  (I-70/I-80S)	In the 1958 plan; became part of I-70 and former I-70 became parts of I-79 and I-76 in 1964
I-70S I-70N	Frederick, Maryland Frederick, Maryland Frederick is a city in north-central Maryland. It is the county seat of Frederick County, the largest county by area in the state of Maryland. Frederick is an outlying community of the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area, which is part of a greater...  (I-70) to Washington, DC (I-66/I-95) and Baltimore, Maryland (I-83/I-95)	In the 1958 plan; became I-270 and I-70 in 1973
I-75E	Bypass for I-75 around Tampa-St. Petersburg, Florida	Renumbered I-275 in 1973, and swapped with I-75 in 1980
I-80N	Echo, Utah Echo, Utah Echo is a census-designated place located in Summit County, Utah, United States. The population was 56 at the 2010 census. Although Echo has never had a sizable population, the town is historically significant.-History:...  (I-80) to Portland, Oregon Portland, Oregon Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...  (I-5)	In the 1958 plan; became I-84 in 1980
I-180N	Spur from I-80N to Boise, Idaho Boise, Idaho Boise is the capital and most populous city of the U.S. state of Idaho, as well as the county seat of Ada County. Located on the Boise River, it anchors the Boise City-Nampa metropolitan area and is the largest city between Salt Lake City, Utah and Portland, Oregon.As of the 2010 Census Bureau,...	This was the only suffixed three-digit Interstate; all other spurs of suffixed routes had no suffix; became I-184 in 1980
I-80S	Big Springs, Nebraska Big Springs, Nebraska Big Springs is a village in Deuel County, Nebraska, United States. The population was 418 at the 2000 census.-Geography:Big Springs is located at ....  (I-80) to Denver, Colorado Denver, Colorado The City and County of Denver is the capital and the most populous city of the U.S. state of Colorado. Denver is a consolidated city-county, located in the South Platte River Valley on the western edge of the High Plains just east of the Front Range of the Rocky Mountains...  (I-25/I-70)	In the 1958 plan; became I-76
I-80N	Neola, Iowa Neola, Iowa Neola is a city in Pottawattamie County, Iowa, United States. The population was 845 at the 2000 census.-Geography:Neola is located at .According to the United States Census Bureau, the city has a total area of , all of it land....  (I-80) to Loveland, Iowa (I-29)	Became part of I-680 in 1973
I-80N Interstate 80N (Ohio) Interstate 80N is a former designation in Ohio. It was replaced by parts of:*Interstate 90*Interstate 480*And the entirety of Interstate 490...	Norwalk, Ohio Norwalk, Ohio At the 2000 census, there were 16,238 people, 6,377 households and 4,234 families residing in the city. The population density was 1,950.3 per square mile . There were 6,687 housing units at an average density of 803.1 per square mile...  (I-80/I-90) to Edinburg, Ohio (I-80)	In the 1958 plan; became part of I-80 by 1962
I-80S	Youngstown, Ohio Youngstown, Ohio Youngstown is a city in the U.S. state of Ohio and the county seat of Mahoning County; it also extends into Trumbull County. The municipality is situated on the Mahoning River, approximately southeast of Cleveland and northwest of Pittsburgh, Pennsylvania...  (I-80) to Camden, New Jersey Camden, New Jersey The city of Camden is the county seat of Camden County, New Jersey. It is located across the Delaware River from Philadelphia, Pennsylvania. As of the 2010 United States Census, the city had a total population of 77,344...  (I-295)	Extended west to Lodi, Ohio Lodi, Ohio Lodi is a village in Medina County, Ohio, United States. The population was 3,061 at the 2000 census.- History :Founded in 1811, Lodi is the oldest settlement in Medina County. It was originally called Harrisville, in honor of the family that founded it. It was later renamed to Lodi, the Indian...  by 1962 over former I-80; east end truncated to Monroeville, Pennsylvania Monroeville, Pennsylvania Monroeville is a home rule municipality in Allegheny County, Pennsylvania, United States. Located about east of the city of Pittsburgh, Monroeville is a bustling suburb with mixed residential and commercial developments...  and the part east of Monroeville renumbered I-76 in 1964; the rest became part of I-76 in 1970
I-81E	Scranton, Pennsylvania Scranton, Pennsylvania Scranton is a city in the northeastern part of Pennsylvania, United States. It is the county seat of Lackawanna County and the largest principal city in the Scranton/Wilkes-Barre metropolitan area. Scranton had a population of 76,089 in 2010, according to the U.S...  (I-81) to Scotrun, Pennsylvania (I-80)	In the 1958 plan; became I-380 ca. 1973