Interstate 170

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For the former route in Baltimore, Maryland, see Interstate 170 (Maryland).

Interstate 170 marker

Interstate 170
Inner Belt Expressway
Route information
Maintained by MoDOT
Length: 11.17 mi[1] (17.98 km)
Existed: 1956 – present
Major junctions
South end: I-64 / US 40 in Richmond Heights
  I-70 in Berkeley
North end: I-270 in Hazelwood
Counties: St. Louis County
Highway system

Missouri Highways

US 169 Route 171

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;[2] 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.[3]

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[edit]

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.[4]

Exit list[edit]

The entire route is in St. Louis County.

Location Mile[5] km Exit Destinations Notes
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
Ladue 1.55 2.49 1F Ladue Road
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
8.83 14.21 9A Airport 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


  1. ^ "Route Log and Finder List - Interstate System - table 2". Federal Highway Administration. 2002-10-31. Retrieved 2007-07-08. 
  2. ^ Sutin, Phil; Hopgood, Mei-Ling (1997-01-09). "Hundreds of Homes Face Razing for New Highway". St. Louis Post-Dispatch. 
  3. ^ Sutin, Phil (1997-03-14). "Westfall Sours On Extension of Interstate 170". St. Louis Post-Dispatch. 
  4. ^ "Project Overview". The New I-64. Missouri Department of Transportation. Archived from the original on 2007-05-04. Retrieved 2007-05-28. 
  5. ^ DeLorme Street Atlas USA 2007, Toggle Measure Tool

External links[edit]

Route map: Google / Bing