The Thruway begins at the Pennsylvania state line in Chautauqua County, following the shore of Lake Erie northeast and passes through the town of Cheektowaga, a large suburb of Buffalo directly east of the city.

Located off exit 1S and Fuller Road Alternate, an unsigned spur of the Northway leading to Western Avenue (US 20), is Crossgates Mall in Guilderland.

I-90 subsequently crosses over NY 5 and passes north of Westgate Plaza as it connects to Everett Road (CR 155).

The freeway continues along the northern edge of Albany to exit 5A,[citation needed] a large trumpet interchange originally built to serve I-687.

East of exit 5A, I-90 passes by slightly more residential areas ahead of a stack interchange with US 9 one mile (1.6 km) north of downtown Albany.

[citation needed] Not far to the east of US 9 is a second stack interchange, connecting I-90 to I-787 in the industrial northeasternmost section of the city of Albany.

At this point, I-90 turns to the southeast and follows the Patroon Island Bridge over the Hudson River and into Rensselaer County.

In its first 1.5 miles (2.4 km) in the county, the freeway meets Washington Avenue at the northern edge of the city of Rensselaer and the west end of NY 43 in the town of North Greenbush, southwest of US 4 and Defreestville.

[citation needed] I-90 heads southeastward across an undeveloped, forested section of the county, crossing over NY 151 and entering the town of Schodack, where it meets Miller Road, a connector between I-90 and the concurrent routes of US 9 and US 20.

[citation needed] I-90 heads southeast on the connector, meeting the north end of the Taconic State Parkway in the Columbia County town of Chatham at exit B2 and NY 22 at exit B3 in the town of Canaan one mile (1.6 km) from the Massachusetts state line.

This highway, passing Utica, Syracuse, and Rochester on its path between Albany and Buffalo, would provide construction jobs in the post-World War II period.

[8] However, construction, which began in 1946, proceeded very slowly, with only one four-mile (6.4 km) portion open by 1950, when a law created the New York State Thruway Authority (NYSTA) to operate the route as a toll road.

Construction then progressed much more rapidly, especially after 1954, when the authority was allowed to issue bonds not backed by the state (thus having higher interest rates).