|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|
|Counties:||St. Louis County|
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 of Hazelwood, Berkeley, St. John, Charlack, Vinita Park, Sycamore Hills, Bel-Ridge, Olivette, Overland, University City, Ladue, Clayton, and Richmond Heights, ending just north of the city of Brentwood.
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.
Recent interchange construction
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 Rd 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||1A-B||I-64 / US 40 – Wentzville, St. Louis||Signed as exits 1A (east) and 1B (west)|
|1C||Eager Road, Brentwood Boulevard north||Southbound exit and northbound entrance|
|Clayton||0.84||1.35||1D||Brentwood Boulevard south||No northbound exit|
|1.12||1.80||1E||Forest Park Parkway|
|University City||2.22||3.57||2||Delmar Boulevard|
|Olivette||3.39||5.46||3||Route 340 (Olive Boulevard)|
|Overland||4.15||6.68||4||Route D (Page Avenue)|
|St. John||5.65||9.09||5||Route 180 (St. Charles Rock Road)|
|Bel-Ridge||6.61||10.64||6||Route 115 (Natural Bridge Road)|
|Berkeley||7.43||11.96||7||I-70 – St. Louis, Kansas City||Signed as exit 7A (east) and 7B (west)|
|7.68||12.36||7C||Lambert-St. Louis Airport||Southbound exit is via exit 7B|
|8.42||13.55||8||Scudder Road, North Hanley Road|
|9.08||14.61||9B||Boeing||Northbound exit and southbound entrance only|
|9.61||15.47||9C||North Hanley Road||Northbound exit and southbound entrance only|
|Hazelwood||10.58||17.03||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.
- DeLorme Street Atlas USA 2007, Toggle Measure Tool