I-190 is a highway running from the mainline Thruway through downtown Buffalo to Niagara Falls and Canada. Originally numbered I-90N prior to the elimination of most suffixed interstates, the majoirty of the route south of Niagara Falls is maintained by the Thruway Authority as the Niagara Thruway. The exit numbers and mileposts on the Niagara Thruway officially have a N prefix (which is not shown on exit signs). The Buffalo Toll Barrier (northbound after I-90) and the Black Rock Toll Barrier (southbound before the Peace Bridge) were both removed due to complaints by the city of Buffalo as part of a deal with the state that included the removal of I-84 from the Thruway system. It is the only signed three digit interstate to cross an international border.
| Mile | Northbound | Southbound | Notes |
|---|---|---|---|
| Erie County | |||
| Speed Limit 55 | |||
| N0.0 |   |
Left Exits 1-52  EastBuffalo Airport Albany |
 East |
| N0.0 | Exits 54-61 West Erie |
West |
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| N0.7 | Exit 1 South Ogden Street Dingens Street |
Exit 1 South Ogden Street |
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| N1.5 | Exit 2  Bailey Avenue Clinton Street |
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| N2.3 | Exit 3 Seneca Street |
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| N3.1 | Exit 4 Smith Street Fillmore Avenue |
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| N3.8 | Exit 5 Hamburg Street |
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| N4.1 | Exit 5 Louisiana Street |
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| N4.6 | Exit 6 Canalside Elm Street |
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| N5.0 | Exit 7 Buffalo Outer Harbor Lackawanna |
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| N5.3 | Exit 7 Church Street Buffalo Outer Harbor |
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| N5.9 | Exit 8 Niagara Street |
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| N6.7 | Exit 9 Peace Bridge Toll Fort Erie Canada Niagara Street |
Exit 9 Porter Avenue Peace Bridge Toll Fort Erie Canada |
To  Toronto |
| N8.7 | Exit 11 Scajaquada Expressway |
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| N9.2 | Exit 12 Amherst Street |
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| N9.4 | Exit 13 Austin Street |
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| N9.9 | Exit 14 Ontario Street |
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| N10.6 | Exit 14 Vulcan Street No trucks over 5 tons |
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| N12.3 | Exit 15 Kenmore Avenue Sheridan Drive |
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| N12.8 | Exit 15 Kenmore Avenue Sheridan Drive |
NY 324 officially joins I-190 at this point but is not signed as such. | |
| N13.4 | Exit 16 East To Tonawanda Rochester |
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| N14.2 | Exit 17 River Road Tonawandas Last exit before toll |
Exit 17 River Road Tonawandas |
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| South Grand Island Bridge Toll | |||
| N15.5 | Exit 18A West Grand Island Boulevard Grand Island Business District |
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| N15.5 | Exit 18B Beaver Island State Park |
Exit 18 Beaver Island State Park Last exit on Grand Island |
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| Speed Limit 65 | Speed Limit 55 | ||
| N17.3 | Exit 19 Whitehaven Road Western New York Welcome Center |
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| N19.3 | Exit 20 Long Road Last exit on Grand Island |
Exit 20B Long Road Grand Island Boulevard |
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| N19.7 | Exit 20A West River Road |
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| Speed Limit 55 | Speed Limit 65 | ||
| North Grand Island Bridge Toll | |||
| Niagara County | Erie County | ||
| N21.2 | Exit 21 Niagara Scenic Parkway Buffalo Avenue |
Exit 21 Buffalo Avenue Last exit before toll |
Northern end of NY 324 |
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| Speed Limit 65 | Speed Limit 55 | ||
| 21.6 | Exit 21A LaSalle Expressway Tonawandas |
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| 22.2 | Exit 22 Niagara Falls Boulevard Business District Airport |
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| 23.7 | Exit 23 Porter Road Packard Road |
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| 23.9 | Exit 23 Porter Road Packard Road |
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| 26.0 | Exit 24 Witmer Road |
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| Speed Limit 55 | |||
| Speed Limit 45 | |||
| 27.7 | Exit 25A Lewiston |
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| Speed Limit 35 | Speed Limit 65 | ||
| 27.7 | Exit 25B Niagara Scenic Parkway Last US exit Last exit before toll |
Exit 25B Niagara Scenic Parkway Lewiston |
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| Speed Limit 15 | |||
| 27.9 | Duty Free Americas | ||
| 28.0 | Export Control | ||
| 28.0 | United States Customs | ||
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To Toronto |
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| Maximum 20 km/h | Speed Limit 15 | ||
| 28.4 | Canada Ontario Niagara Regional Municipality |
United States New York Niagara County |
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