I-255

Interstate 255
Route information
Maintained by IDOT and MoDOT
Length:	30.82 mi (49.60 km)
Existed:	1967 (completed 1986) – present
Major junctions
South end:	I-55 / I-270 in Mehlville, MO
	US 50 / US 61 / US 67 in Mehlville, MO I-64 / US 50 in Washington Park, IL I-55 / I-70 / US 40 in Collinsville, IL
North end:	I-270 / IL 255 in Pontoon Beach, IL
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future ← Route 254 MO Route 265 → ← IL 251 IL IL 255 →

Interstate 255 (I-255) is a bypass route of Interstate 55 near St. Louis, Missouri and with Interstate 270, it forms a loop around the city. Even though St. Louis is in Missouri, a majority of the route runs through Illinois. It shares its southern terminus with 270 at the junction with Interstate 55, 270 goes to the west and 255 goes to the east. US 50 joins I-255 at Lemay Ferry Road. It crosses the Mississippi River on the Jefferson Barracks Bridge, enters Illinois, and then turns north. There is a junction with Interstate 64, where US-50 breaks off and goes east, and then further north there is a junction with Interstate 55 again, Interstate 70, and U.S. Route 40, all of which are all co-signed together. The next junction is another one with Interstate 270, and it is the northern terminus of Interstate 255. After that, it becomes Illinois Route 255.

Interstate 255 is 30.82 miles (49.60 km) in length.

I-255 route was proposed from I-55/I-244 near Green Park to I-55/70 west of Cahokia Mounds near the intersection with IL 111 when plans surfaced in the 1950s Yellow Book. It was originally designed to be a four lane highway but was changed to six lanes.

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Wikipedia