Virginia State Route 404 is the shortest at just over 0.5 mile in length.
NY 404 was an early 20th-century auto trail, which largely follows the path of the Theodore Roosevelt International Highway (which goes from Portland, ME to Portland, OR).
New Mexico State Road 404 runs across a gap between the northern edge of the Franklin Mountains and the southern edge of the North Franklin Mountains.
Iowa 404 (a portion of US 75 Business) is never signed as such.
Interstate 16 (I-16), also known as Jim Gillis Historic Savannah Parkway carries the hidden designation of State Route 404 (SR 404) for its entire length.
Florida State Road 404 (SR 404), aka the Pineda Causeway, is arguably the most scenic.