Endpoints of
US Route 6

Claims to fame:

• From 1937-1963, US 6 ran about 3500 miles from coast to coast.  That was the greatest length of any US route, current or historic.  (More about its mileages and its midpoints.)

• US 6 reaches 11,990' at the summit of Loveland Pass in Colorado, which is the highest elevation of any US route that is open year-round.  (That is about 200' lower than US 34's high point along Trail Ridge Road, but that highway is open only during the summer months.)

Judging from the volume of feedback US Ends .com receives regarding US 6, this route seems to capture the interest of road enthusiasts more than most other US highways. In Jack Kerouac's 1951 novel On the Road, the main character described US 6 as "one great red line across America".  ​There is something fascinating about a road that is mostly rural, yet still stretches nearly the length of the entire country.  And the way it follows the spiral of Cape Cod is particularly endearing.  In the late 1930s (when it was extended west from Denver to the Los Angeles area), US 6 became the longest highway in the history of US routes.

The early history of US 6 is complicated, primarily because it was planned to go through New York and Pennsylvania.  New York wanted only a few US routes, and US 6 was not among them (that was also the case with several other routes, and for that reason, many US routes initially ended at the NY state line).  In contrast, New York's neighbor to the south and west, Pennsylvania, wanted lots of its highways to be given US route designations.  However, Pennsylvania was notorious for making several revisions to its routes, many of them shortly after the "final" plan was approved in November 1926.

The 1925 plan had US 6 running from Provincetown to Brewster NY (by which they meant the New York state line just west of Danbury CT).  After changes that resulted in the plan's actual approval by the states in late 1926, the map included two disconnected segments of US 6: an east leg as described above, and a west leg running between Matamoras and Kane PA (where US 6 was to end at its junction with US 120).  In other words, initially US 6 had a gap in New York.  But by the time an April 1927 route log was published, New York had agreed to accept US 6... however, it went northeast from Matamoras to Kingston (along what eventually became US 209), and there still was no US 6 between Kingston and Danbury.  On its west end, Pennsylvania planned to truncate US 120, and instead it was US 6 that would be extended to Erie.

However, it appears that neither Pennsylvania nor New York actually signed their portions of the highway with US 6 markers until 1928, and by then the route had changed again.  The two separate segments had been joined using the more direct corridor between Brewster and Matamoras, so when US 6 was first signed, it essentially followed its current alignment from Provincetown all the way to Union City PA.  From that point, US 6 was routed northwest to end at US 20 (more info on the Erie page).  The segment of the earlier-planned US 6 that was to run between Kingston and Matamoras was designated US 6N[i].

In the early 1930s, the US 6 designation got a major extension to the west, through Cleveland and the Chicago area.  From there, the new US 6 swallowed up US 32 all the way to Council Bluffs, and retired US 38 from Omaha to Greeley CO, where it ended at US 85 (more info on the Greeley page).  This was the letterhead of a Route 6 organization during the brief timeframe when US 6 ran from Provincetown to Greeley:

By 1933, US 6 went from Union City through Edinboro to US 20 at West Springfield, bypassing Erie to the south.  Its former route from Union City to Erie was then designated US 6N[ii].  Around this time, US 6N[i] between Kingston and Port Jervis was decommissioned (US 209 was extended north along that route by 1935).  US 6N[ii] lasted only a few years, because in the mid- to late-1930s, the route of US 6 was changed again: this time to its current alignment through Meadville PA.  At that time, US 6N[ii] was decommissioned, and that designation was instead re-applied to a third route: the modern US 6N[iii] running between West Springfield and Mill Village PA.

In 1937, US 6 was extended all the way to the west coast.  Its former segment between Wiggins CO and Greeley became part of US 34.  US 6 instead went from Wiggins along the "Denver Cutoff" to its eponymous city, and then west essentially along its current route to Bishop CA.  From there, US 6 was co-signed with US 395 to a junction near Inyokern, and then south along today's CA hwy. 14 into greater Los Angeles.  More info about the historic westernmost terminus of US 6 can be found on the Long Beach page.  Here is the letterhead from the same organization, updated after US 6 was extended to the Pacific:

US 6 basked in the glory of its coast-to-coast, longest-US-route status for nearly 30 years.  But in 1963 the designation was truncated to its current terminus, leaving only about 40 miles of US 6 in CA (more info on the Bishop page).