New York State Route 1B

Major Deegan Expressway
Major William Francis Deegan Expressway
Map of the Bronx in New York City with Major Deegan Expressway highlighted in red
Route information
Maintained by NYSDOT
Length:	8.70 mi (14.00 km)
Existed:	April 1939 – present
History:	Completed in 1956
Major junctions
South end:	I-278 in the Bronx
	I-95 / US 1 in the Bronx Mosholu Parkway in the Bronx
North end:	I-87 / New York Thruway at the Westchester County line
Highway system
Interstate Highway System Main Auxiliary Suffixed Business New York Highways Interstate U.S. State Reference Parkways ← NY 1A NY 1X →

The Major Deegan Expressway, officially named the Major William Francis Deegan Expressway and locally known as the Deegan, is a north–south expressway in the New York City borough of the Bronx. It is the southernmost 8.70 miles (14.00 km) of Interstate 87 (I-87), beginning at I-278 at the interchange of the Bruckner Expressway and the Triborough Bridge in the south Bronx and ending at the Westchester County line in Yonkers, where the New York State Thruway begins. In between, the Major Deegan Expressway winds through Van Cortlandt Park, intersects with I-95 (the Cross Bronx Expressway) near the George Washington Bridge, and passes by Yankee Stadium on its eastern flank.

The expressway was completed in 1956 and became part of I-87 when that highway was assigned as part of the creation of the Interstate Highway System in 1957. It is named for William Francis Deegan, who died in 1932. He was an architect, a Major in the Army Corps of Engineers and a Democratic political leader in New York City.