As of 2018, US 400 measured 481 miles in total length.
US 400 was commissioned in 1994. Its east end is outside Joplin, at its interchange with I-44. Originally the west end of US 400 was in Garden City; there was only one issue of the Kansas official state highway map illustrating that: |  c. 1995, KS DoT |
This first photo was looking south on the US 50-83 bypass, at the interchange where US 50-400 traffic exits onto Fulton Street: |  Sanderson, Nov. 2001 |
That bypass had already been built by the time US 400 was commissioned, so it is likely that the sign above marked the exit to the west beginning of US 400. These shots were looking west on Fulton (US 50-400): |  Sanderson, Nov. 2001 |  Sanderson, Mar. 2018 |
Today the bypass carries US 83, and US 50-400 traffic is routed onto it too. But when it was first commissioned, the US 400 designation ended at that interchange. One could argue that US 400 should not have ever made it even as far west as Garden City -- there is no good reason why it couldn't end at its junction with US 50 in Dodge City. But clearly KDoT had a different opinion: for whatever reason, they must have wanted US 400 to run across the entire state, because within two years US 400 had been signed even further west with US 50, through the remainder of Kansas. Since then, the west end of US 400 is about 15 miles west of the Kansas border, in Granada. In other words, the westernmost 131 miles of US 400 are on a pointless overlap with US 50.
Until recently, CDoT signage in Granada did not even bother mentioning US 400, and there were a grand total of two US 400 signs in Colorado. Here are photos of the last westbound US 400 sign: |  Wiley, 2000 |  Sanderson, Mar. 2018 |
That sign is between Holly and Granada; it was posted just past Prowers Co. Rd. 30, which goes north to serve the town of Hartman. Not far ahead, travelers reach the town of Granada -- these photos were looking west on Goff Avenue (US 50). US 400 is co-signed with US 50 to this point, but here at Main Street (US 385) that designation ends: |  Sanderson, Nov. 2001 |  Sanderson, Mar. 2018 |
These shots were looking the opposite direction (east on US 50-385). From here, US 385 heads north on Main, while US 50 continues ahead on Goff. The US 400 designation also begins ahead: |  Sanderson, Nov. 2001 |  Riner, Aug. 2005 |  Sanderson, Mar. 2018 (same as of 2021) |
That was the only mention of US 400 at its terminus in Granada; by 2005 the other sign assemblies had also been replaced, but none of the others included any reference to US 400. (Incidentally, it is odd that there was a CO hwy. 196 marker on that eastbound assembly. To get there, one crosses the Arkansas River via US 385, and then 196 begins by heading back to the west -- likely not a very common traffic pattern. The intention may have been to have that marker included on the westbound assembly, but a mistake was made somewhere along the line.)
Following are more photos of the same intersection; these were looking south on Main, or US 385: |  Sanderson, Nov. 2001 |  Sanderson, Mar. 2018 (same as of 2021) |
From there, if a driver turns left, they are on US 400 as well as US 50. Heading that direction, one quickly encounters the first confirming marker: |  Sanderson, Nov. 2001 |  Sanderson, Mar. 2018 |
Research and/or photocredits: Alex Nitzman; Steve Riner; Dale Sanderson; Mike Wiley Page originally created 2000;
last updated Apr. 09, 2021.