List of unsigned auxiliary Interstate Highways

Some auxiliary Interstate Highways are not signed, typically because the routes are already known by another name, and marking them could confuse motorists. A small fraction of three-digit Interstates, especially very short ones (in terms of physical length), are not signed.

Interstate	Vicinity	Description
I-305	Sacramento, CA	Signed as US 50 and Business Loop I-80. It was part of I-80 until October 1983.
I-910	New Orleans, LA	Signed as Business Route US 90.
I-315	Great Falls, MT	Signed as Business Loop I-15.
I-124	Chattanooga, TN	Signed as US 27.
I-444	Tulsa, OK	Signed as US 75.
I-345	Dallas, TX	Signed US 75 (northbound) I-45 (southbound).
I-478	New York City, NY	Signed as the Brooklyn-Battery Tunnel.
I-878	New York City, NY	Signed as SR 878.
I-480 N	Cleveland, OH	Signed as a connection between I-480 and I-271/US 422.
I-194	Bismarck, ND	Signed as SH 810.
I-495	Falmouth, ME	Signed as a connection between I-95 and I-295. It was redesignated from part of I-95 on January 5, 2004 Also known as the Falmouth Spur of the Maine Turnpike, with mile markers starting with the prefix FS-.
I-595	Annapolis, MD	Signed as US 50 from the Washington, D.C., area east to Annapolis, Maryland.
I-296	Grand Rapids, MI	Signed as US 131.