The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Highway System in the United States. The system extends throughout the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.
Interstate 385 (I-385) is an auxiliary Interstate Highway located in the Upstate region of South Carolina. I-385 is a spur route of I-85. The highway provides a connection between Greenville and I-26 to the south, connecting Greenville to Columbia and Charleston. Around Greenville, the last several miles of I-385 forms the northeastern quadrant of a partial beltway around Greenville's southern suburbs along with I-185.
Interstate 515 (I-515) is a 14.44-mile-long (23.24 km) spur route of I-15 in the US state of Nevada that runs from the junction of I-11, I-215, and State Route 564 (SR 564) at the Spaghetti Bowl Interchange in Henderson to the junction of I-15, U.S. Route 93 (US 93), and US 95 at the Las Vegas Spaghetti Bowl Interchange in Downtown Las Vegas. The freeway connects traffic headed from Boulder City and Henderson to Downtown Las Vegas via a direct, high-speed route, and it runs concurrently with, US 93, and US 95 along its entire length.
Interstate 296 (I-296) is a part of the Interstate Highway System in the US state of Michigan. It is a north–south state trunkline highway that runs for 3.43 miles (5.52 km) entirely within the Grand Rapids area. Its termini are I-196 near downtown Grand Rapids and I-96 on the north side of Grand Rapids in Walker. For most of its length, the Interstate runs concurrently with U.S. Highway 131 (US 131), which continues as a freeway built to Interstate Highway standards north and south of the shorter I-296. The highway was first proposed in the late 1950s and opened in December 1962, but the Michigan Department of Transportation (MDOT) has since eliminated all signage for I-296 and removed the designation from their official state map. The designation is therefore unsigned, but still listed on the Interstate Highway System route log maintained by the Federal Highway Administration (FHWA).
Interstate 180 (I-180) is a 1.09-mile-long (1.75 km) connector in the US state of Wyoming between I-80 and downtown Cheyenne.
The Falmouth Spur is a short freeway connecting Interstate 95 (I-95) with I-295 and US Route 1 (US 1) north of Portland, Maine, in the United States. It carries the unsigned designation of Interstate 495 (I-495). As part of the Maine Turnpike, the mainline of which carries I-95, the Falmouth Spur is a toll road. The spur has only two interchanges—one at each end—and a toll booth in the middle. It is signed only for its destinations—I-95, I-295, and US 1—to minimize driver confusion.
Interstate 190 (I-190) is an auxiliary Interstate Highway in the US state of South Dakota. The route runs for about two miles (3.2 km) connecting I-90 to downtown Rapid City. The entire route is concurrent with US Highway 16 (US 16). It is the westernmost auxiliary route of I-90 and its only auxiliary route west of the Mississippi River.
Interstate 280 (I-280) is an auxiliary Interstate Highway that makes up the western and southern portions of the beltway around the Quad Cities of Illinois and Iowa. The freeway starts at I-80 near Davenport, Iowa, and ends at I-80 near Colona, Illinois; its eastern part runs concurrent with I-74 to return to I-80. I-280 forms the southern part of a circle around the Quad Cities as well as forming part of a bypass for US Route 61 (US 61) around Davenport. This road is 26.98 miles (43.42 km) long.
Interstate 41 (I-41) is a 175.00-mile-long (281.64 km) north–south Interstate Highway connecting the interchange of I-94 and U.S. Route 41 (US 41), located 2.50 miles (4.02 km) south of the Wisconsin–Illinois border at the end of the Tri-State Tollway in metropolitan Chicago, to an interchange with I-43 in metropolitan Green Bay, Wisconsin. The designation travels concurrently with US 41 for its entire length, as well as portions of I-894, US 45, I-43, and sections of I-94 in Wisconsin and Illinois. The route was officially added to the Interstate Highway System on April 7, 2015, and connects Milwaukee and Green Bay with the Fox Cities.
Interstate 285 (I-285) is a 23.49 mile long auxilary interstate highway connecting the cities of Lexington and Winston-Salem, in the U.S state of North Carolina. The route was approved in February 2018 and was first signed in November 2018. An auxiliary route of I-85, it branches off of its parent route and runs northeast, bypassing central Lexington, before turning due north and heading toward Winston-Salem, terminating at an interchange with I-40. I-285 is cosigned with US Highway 52 (US 52) for its entire route, and as of November 2018, still uses US 52 milemarkers and exit numbers. Other routes cosigned along parts of the route include I-85 Business, US 29, US 70, and North Carolina Highway 8 (NC 8). I-285 has been approved for an extension along the US 52 freeway through Winston-Salem to meet the future Winston-Salem Northern Beltway.
Interstate 795 (I-795) is a 25.49-mile (41.02 km) auxiliary Interstate Highway in the US state of North Carolina. It connects the city of Goldsboro to I-95 just south of Wilson, paralleling the northern portion of US Route 117 (US 117). The road runs a five-mile (8.0 km) concurrency with US 264 and I-587 in the last section of the route. It serves as a primary freeway spur for the city of Goldsboro to the Interstate Highway System, as well part of a major cargo route for the cities of Down East, which was a part of the impetus for its designation in 2007.
Interstate 87 (I-87) is a partially completed Interstate Highway in the US state of North Carolina, the shortest designated primary Interstate Highway at 12.90 miles (20.76 km). The completed portion is in eastern Wake County, between Raleigh and Wendell; the majority of the completed route is known as the Knightdale Bypass, while the remaining three miles (4.8 km) follows the Raleigh Beltline (I-440). It is planned to continue northeast through Rocky Mount, Williamston, and Elizabeth City, ending in Norfolk, Virginia. It is signed as north–south, in keeping with the sign convention for most odd-numbered interstates, but the route goes primarily east–west, with the eastern direction aligning to the north designation. The entire route is concurrent with US Highway 64 (US 64), with portions also concurrent with I-440 and US 264.
Interstate 587 (I-587) is a 37.07-mile (59.66 km) auxiliary Interstate Highway in the US state of North Carolina. The western terminus of the highway is at I-95, I-795, and US Highway 264 (US 264) near Wilson. The highway runs concurrently with I-795 and US 264 around the southern side of Wilson. I-795 diverges toward Goldsboro 4.4 miles (7.1 km) east of I-95. The eastern end of the US 264 overlap is located northwest of Saratoga. I-587 continues travelling east, bypassing Saratoga and Farmville to the north. The eastern terminus of I-587 is located at US 264 and North Carolina Highway 11 Bypass in western Greenville. I-587 is a spur of the North Carolina segment of I-87 which runs from Raleigh to Wendell. As of 2023, I-587 does not connect with its parent route.
