|Inner Belt Expressway|
|Maintained by MoDOT|
|Length:||11.17 mi (17.98 km)|
|Existed:||1956 – present|
|South end:||I-64 / US 40 in Richmond Heights|
|I-70 in Berkeley|
|North end:||I-270 in Hazelwood|
Interstate 170 (I-170) is the designation for an interstate route in the St. Louis, Missouri metropolitan area. I-170, also known as the Inner Belt Expressway, is an 11.17-mile (17.98 km) highway traveling north-south through the St. Louis suburbs.
I-170 connects to Interstate 270 at its northern terminus and Interstate 64 at its southern terminus; at exits 7A and 7B, I-170 crosses its parent, I-70. Interstate 170 also provides access to Lambert-St. Louis International Airport.
I-170 was originally intended to provide an inner beltway within I-270 through St. Louis County extending to I-55 in the South County area; however, the portion of the route south of I-64/US 40 was canceled due to local opposition. The portion of MetroLink's Cross County Extension south of I-64 runs roughly along the proposed alignment.
The southern portion of I-170 was built using St. Louis County funds in the 1960s through a shallow valley. It was signed as Route 725.
The southern two interchanges on I-170 (at I-64/US 40 and Galleria Parkway) were reconstructed as part of the first phase of the New I-64 project. Most notably, the new interchange includes direct access to I-170 from eastbound I-64; however, access to Galleria Parkway from northbound I-170 was eliminated. Eager Road access to and from I-170 was also revised in the New I-64 project.
The entire route is in St. Louis County.
|Richmond Heights||0.00||0.00||1||I-64 / US 40 / Lewis and Clark Trail – Wentzville, St. Louis||Signed as exits 1A (east) and 1B (west)|
|0.438||0.705||1C||Brentwood Boulevard north / Eager Road||Southbound exit and northbound entrance|
|Clayton||0.809||1.302||1D||Brentwood Boulevard south||Southbound exit and northbound entrance (via Galleria Parkway)|
|1.170||1.883||1E||Forest Park Parkway east||Western terminus of the Forest Park Parkway|
|University City||2.374||3.821||2||Delmar Boulevard|
|Olivette||3.336||5.369||3||Route 340 (Olive Boulevard)|
|Overland||4.325||6.960||4||Route D (Page Avenue)|
|St. John||5.865||9.439||5||Route 180 (St. Charles Rock Road)|
|Bel-Ridge||7.027||11.309||6||Route 115 (Natural Bridge Road) – Cargo City|
|Berkeley||7.654||12.318||7||I-70 – St. Louis, Kansas City||Signed as exit 7A (east) and 7B (west); exit 235|
|7.771||12.506||7C||Lambert–St. Louis International Airport||Southbound exit is via exit 7B|
|8.577||13.803||8||Scudder Road / North Hanley Road||No northbound entrance|
|9.167||14.753||9A||Airport Road – Cargo City|
|9.236||14.864||9B||Boeing||Northbound exit and southbound entrance|
|9.780||15.739||9C||North Hanley Road||Northbound exit and southbound entrance|
|10||I-270 – Kansas City, Chicago||Signed as exits 10A (west) and 10B (east)|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi
- "Route Log and Finder List - Interstate System - table 2". Federal Highway Administration. 2002-10-31. Retrieved 2007-07-08.
- Sutin, Phil; Hopgood, Mei-Ling (1997-01-09). "Hundreds of Homes Face Razing for New Highway". St. Louis Post-Dispatch.
- Sutin, Phil (1997-03-14). "Westfall Sours On Extension of Interstate 170". St. Louis Post-Dispatch.
- "Project Overview". The New I-64. Missouri Department of Transportation. Archived from the original on 2007-05-04. Retrieved 2007-05-28.
- Missouri Department of Transportation (March 18, 2015). Flex Map Viewer (Map). Missouri Department of Transportation. Retrieved March 18, 2015.