Home > Multiplexes > Superlatives

Highway Multiplexes:
The Most, The Longest, The Most Routes, The Most Duplicates and more

 

Current Multiplex Counts by State (Interstates, US Routes, and State Routes only)

State	Multiplexes	Duplexes	Triplexes	Quadruplexes	5+ -plexes
Alaska	1	1	–	–	–
Connecticut	114	106	7	1	–
Delaware	65	59	6	–	–
District of Columbia	5	5	–	–	–
Florida
Hawaii	–	–	–	–	–
Indiana
Maryland	57	50	6	1	–
Massachusetts	175	158	17	–	–
Michigan
New Jersey
New York	227	185	38	4	–
Ohio
Pennsylvania	428	394	31	3	1 (5)
Rhode Island	46	41	3	2	–
Virginia (list)	286	239	41	6	–
Washington	40	35	5	–	–
Québec	104	97	7	–	–

 

Longest Duplexes by State/Province/Country

State/Province/ Country	Longest Duplex	Length (miles)	Location
United States
Canada
Alaska	AK 1/AK 4	14	Gakona Junction
Connecticut
Delaware		12.42	Georgetown
District of Columbia		2	Washington
Florida
Indiana
Maryland		67.3	Keysers Ridge to Hancock
Massachusetts
Michigan
New Jersey
New York		79	Avon to Auburn
Ohio
Pennsylvania		*87.22	New Stanton to Breezewood
Rhode Island
Virginia
Washington
Québec

*When I-99 is extended northward past I-80 to I-180/US 15 (in 201x?), I-99/US 220 will be the longest PA multiplex at about 135 miles long.

 

Longest Triplexes by State/Province/Country

State/Province/ Country	Longest Triplex	Length (miles)	Location
United States
Canada
Alaska	–	–	–
Connecticut
Delaware		3.40	Summit Bridge
District of Columbia	–	–	–
Florida
Indiana
Maryland		11.9	W of Annapolis
Massachusetts
Michigan
New Jersey
New York
Ohio
Pennsylvania
Rhode Island
Virginia
Washington
Québec

 

Longest Quadruplexes by State/Province/Country

State/Province/ Country	Longest Quadruplex	Length (miles)	Location
United States
Canada
Alaska	–	–	–
Connecticut
Delaware	–	–	–
District of Columbia	–	–	–
Florida
Indiana
Maryland		1.4	Annapolis
Massachusetts
Michigan
New Jersey
New York
Ohio
Pennsylvania		1	Pittsburgh
Rhode Island
Virginia		5.75	E of Wytheville
Washington
Québec

 

Current Duplicated Multiplexes by State/Province/Country

Duplicated Multiplexes	Count	Locations North to South or West to East
Interstate/Interstate
	2	Tomah, WI to Madison, WI Chicago, IL
Interstate/US Route
	6	San Antonio, TX Alleyton, TX Brookshire, TX Houston, TX Beaumont, TX Lake Charles, TX
	4	Lehi, UT North Salt Lake, UT Centerville, UT Great Falls, MT
	4	Jonesville, TX Mound, LA to Vicksburg, MS Edwards, MS to Clinton, MS Meridian, MS
	2	Casper, WY Douglas, WY
	2	Casper, WY Douglas, WY to Dwyer, WY
	3	Cheyenne, WY Denver, CO Castle Rock, CO to Co/NM border
	2	Buffalo, WY to Casper, WY Douglas, WY to Raton, NM
	2	Lubbock, TX Tulia, TX
	2	St. Joseph, MO Fillmore, MO
	2	Fargo, ND Pembina, ND
	2	Kansas City, KS Liberty, MO
	4	Waco, TX Gainesville, TX Moore, OK Edmond, OK
	2	Whitsett, TX San Antonio, TX
	3	Wausau, WI to Stevens Point, WI Plover, WI to Portage, WI South Beloit, IL to Normal, IL
	2	Burkburnett, TX Lawton, OK
	2	Akers, LA Jackson, MS
	2	Hayti, MO Scott City, MO
	3	McCalla, AL Meridian, MS Nicholson, MS to Alton, LA
	3	Callaghan, VA Clifton Forge, VA Hampton, VA
	3	Warrior, AL Thach, AL
	7	Great River, UT to Mack, CO Palisade, CO to Parachute, CO Parachute, CO to Rifle, CO New Castle, CO to Gypsum, CO Vail, CO to Dillon, CO W of Georgetown, CO to Idaho Springs, CO Denver, CO
	3	Limon, CO to Siebert, CO Burlington, CO to Levant, NE Kansas City, KS to Kansas City, MO
	12	Lawson to Golden, CO Aurora to Limon, CO Campus to Topeka, KS Kansas City, KS & MO Blue Springs, MO to Wentzville, MO East Saint Louis, IL Pocahontas, IL E of Marshall, IL Fairview, OH Wheeling, WV Hancock, MD Mount Airy, MD
	3	Elkin, NC to Jonesville, NC Mooresville, NC to Lake Norman, NC Charlotte, NC to S of NC/SC line
	2	N of Rocky Gap, VA E of Wythewville, VA
	2	Fredericksburg, PA to Allentown, PA Bloomsbury, NJ to Lebanon, NJ
	4	Lorah, IA to Dexter, IA Altoona, IA to Lambs Grove, IA Durant, IA to Davenport, IA Gary, IN
	3	Green River, WY to Walcott, WY Laramie, WY to Cheyenne, WY E of Cheyenne, WY to Pine Bluffs, WY
	2	E of Wytheville, VA S of Natural Bridge, VA
	3	Danbury, CT Newtown, CT to Southbury, CT Farmington, CT to Manchester, CT
	11	Portland, OR Bonneville, OR to Cascade Rocks, OR Cascade Rocks, OR to Hood River, OR Hood River, OR to Mosier, OR The Dalles, OR to Pendleton, OR Pendleton, OR to La Grande, OR La Grande, OR to North Powder, OR Baker City, OR to Lime, OR S of Huntington, OR to Palisades Corner, ID Fruitland, ID to Bliss, ID Burley, ID to E of Rupert, ID
	4	Greensboro, NC to High Point, NC Lexington, NC to Spencer, NC Kings Mountain, NC to Grover, NC Greenville, SC to Anderson, SC
	2	Missoula, MT to Garrison, MT Forsyth, MT to Miles City, MT
	4	Sheridan, WY Gillette, WY to Moorcroft, WY Sundance, WY to Wall, SD Dresbach, MN
	2	Buffalo, WY Wyola, MT
	3	Miles CIty, MT St. Paul, MN Ann Arbor, MI
	2	Milwaukee, WI to N of Wadsworth, IL Northbrook, IL
	5	Norwood, MA Pawtucket, RI New London, CT Old Lyme, CT New York City, NY to Fort Lee, NJ
	2	Fredericksburg, VA Coosawatchie, SC
	2	Lumberton, NC Santee, SC
	2	Fort Smith, AR Fayetteville, AR
Interstate/State Route
	2	Niagara Falls, NY Buffalo, NY
US Route/US Route
	2	Sanford, NC Southern Pines, NC
	2	Lexington, SC Columbia, SC
	2	Raleigh, NC Wise, NC
	3	Freemont, OH Cleveland, OH Euclid, OH
	2	Holdrege, NE Princeton, IL
	2	Hartford, CT Providence, RI
	2	Delta, UT Grand Junction, CO
	2	Peekskill, NY Brewster, NY to Danbury, CT
	2	Cleveland, OH Meadville, PA
	2	Danbury, CT Brookfield, CT
	2	Chicago, IL Gary, IN
	2	Yellowstone Nat'l Park, WY to Cody, WY Uctoss, WY to Moorcroft, WY
	2	Ranger, NC to Lauada, NC Dellwood, NC
	2	Tazewell, VA Princeton, WV
	3	Vale, OR to Mountain Home, ID Butte City, ID to Atomic City, ID Shoshoni, WY to Orin, WY
	2	Atlanta, GA Athens, GA
	2	Fort Dodge, KS to Kingsley, KS Gardner, KS to Overland Park, KS
	2	Lufkin, TX Narcissa, OK
	2	Savannah, MO Acorn, AR to Texarkana, AR
	3	Cairo, IL to Wickliffe, KY Paducah, KY Versailles, KY
	2	Frankfort, KY Lexington, KY
	2	Davenport, IA Kirkwood, MO to Crystal City, MO
	2	Brownfield, TX Lorenzo, TX
	2	Raleigh, NC to Wendell, NC Manteo, NC to Nags Head, NC
	2	Enid, OK Tulsa, OK
	2	Whiteville, NC to Wilmington, NC Wrightsville, NC
	2	Mobile, AL Spanish Fort, AL
	2	Rosston, AR Nashville, AR
US Route/State Route
	2	Schuylerville, NY Mechanicville, NY
	2	Croton-on-Hudson, NY Yonkers, NY
	2	Elizabethtown, NY Lake George, NY
US 9W	3	Saugerties, NY Kingston, NY Newburgh, NY
	2	Whitney Point, NY Evans Mills, NY
	2	Irving to Silver Creek, NY Avon to Auburn, NY
MI 26	2	Phoenix, MI Houghton, MI
	2	Miami, OK Grove, OK to Kansas, OK
KS 7	2	Fort Scott, KS Columbus, KS
CA 1	3	San Francisco, CA San Luis Obispo, CA Las Cruces to Ventura, CA
	2	Lancaster, PA Wakefield, PA
State Route/State Route
	2	Maysville, KY Charters, KY
	2	Blue Mountain, NY to Indiana Lake, NY Margaretville, NY
WI 32/WI 57	2	De Pere, WI Mequon, WI

 

Sources: Adam Froehlig, Douglas Kerr, Dan Moraseski, various maps and atlases, the newsgroup misc.transport.road, and the multiplex sites linked in the first table.