Interstate 205 (California)

Interstate 205
Interstate 205
Robert T. Monagan Freeway
	I-205 highlighted in red
Route information
	Auxiliary route of I-5
	Maintained by Caltrans
Length	12.97 mi (20.87 km)
Existed	December 1970–present
History	State highway in 1910
NHS	Entire route
Major junctions
West end	I-580 near Tracy
East end	I-5 near Lathrop
Location
Country	United States
State	California
Counties	Alameda, San Joaquin
Highway system
	Interstate Highway System; Main; Auxiliary; Suffixed; Business; Future; State highways in California; Interstate; US; State; Scenic; History; Pre‑1964; Unconstructed; Deleted; Freeways;

Interstate 205 (I-205) is an east–west auxiliary Interstate Highway in the San Joaquin Valley in Northern California. It runs from I-5 west to I-580. Along with those highways, I-205 forms the north side of a triangle around the city of Tracy. The route provides access from the San Francisco Bay Area to the northern San Joaquin Valley.

When I-205 opened in December 1970, it replaced 11th Street, which passed through downtown Tracy, as part of the primary all-land connection between the Bay Area and Sacramento until the Carquinez Bridge opened in 1927 and carried the Lincoln Highway and later US Route 50 (US 50). 11th Street is now signed as I-205 Business (I-205 Bus.).

^ Starks, Edward (January 27, 2022). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways". FHWA Route Log and Finder List. Federal Highway Administration. Retrieved March 19, 2023.

[1] Starks, Edward (January 27, 2022). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways". FHWA Route Log and Finder List. Federal Highway Administration. Retrieved March 19, 2023.

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