Embedded Files
100 years of US routes: 1926-2026
Endpoints of
1926-1927
North: Harrisburg, PA
South: Washington, DC
1927-1972
North: Frederick, MD
South: Washington, DC
The US 240 designation had a sketchy early history in Pennsylvania. The map that AASHO approved in 1926 showed US 240 not only from Washington DC to Frederick, but also from there up to Harrisburg. That was because at the time US 15 was planned to go only as far north as Virginia. However, already by the time of AASHO's April 1927 route log, US 15 was in Harrisburg. Thus there was no need for US 240 to extend north of Frederick, so it was never signposted anywhere in Pennsylvania:
c. 1939, Rand McNally
Frederick
This map of Frederick suggests that US 240 ended at its junction with US 15 south of town...
c. 1938, MD DoT
...however, it is more likely that US 240 would have been dual-signed with US 15, ending at its "parent" route (US 40). This photo was taken looking north on Market Street; US 240 probably ended here at Patrick Street:
Brooks, Aug. 2019
That intersection is known as Frederick Square Corner; interpretive markers there attest to the historic importance of that crossroads.
This photo was taken looking west on Patrick, which today carries MD hwy. 144 traffic, but historically served as US 40. To the left on Market was the north beginning of US 240:
Mortell, Aug. 2007
I-70S (now I-270) was complete by 1959, and US 240 traffic was rerouted to follow this faster road. At that time (according to a historic list of route numbering changes in Maryland), the designation was changed such that it ended at the same interchange where I-270 ends today. This photo shows signage at the north end of I-270, and at what was the north end of US 240 until it was decommissioned in 1972:
aaroads.com, Aug. 2013
Washington
From Frederick, US 240 originally followed what is now MD 355 into the District, entering on Wisconsin Avenue, then turning onto Massachusetts Avenue. But from there the D.C. routing changed over the years. The earliest map I have seen with detail about US 240's route (1937) shows that the route actually crossed into Virginia before ending at US 1. These slightly-later maps showed that same arrangement...
c. 1940, Rand McNally
...but then there was a brief time during the mid-1940s when US 240 ended at the White House (or, more accurately, the Zero Milestone on the Ellipse south of the White House). Apparently US 240 went south on 17th Street, then east on "E" Street to its terminus. Even though this USGS map suggests it ended on Pennsylvania Avenue at jct. US 1 (14th Street)...
c. 1942, Esso
c. 1945, USGS
...the District's 1946 application to AASHO expressly noted the Zero Milestone as the terminus:
That also described US 240's new endpoint (17th at Independence Avenue), but there are reasons to doubt it was ever signposted that way. For one thing, DC's 1946 application seems to have included two different maps showing proposed changes to US route alignments. One illustrated US 240 ending as described above, but the other showed US 240 ending at the Lincoln Memorial. And a few months after AASHO approved DC's proposed changes, they asked the District Dept. of Highways for a route log, and the one they received defined US 240's terminus as the Lincoln Memorial:
So most maps throughout the 1950s show US 240 back on its older alignment, but instead of crossing the Arlington Memorial Bridge, the route ended at its junction with US 50 at the Lincoln Memorial:
c. 1951, USGS
c. 1956, Gousha
By the time of AASHO's 1969 route log, US 240 was back to using Connecticut and 17th; but this time the designation continued past "E", ending instead on 17th at Constitution Avenue, which had recently become the route of US 50 (that happened when the Theodore Roosevelt Bridge opened in about 1960, and US 50 traffic stopped using the Arlington Memorial Bridge). That was its final routing at the time of its decommissioning in 1972; following is that agenda item from the minutes of AASHO's meeting in June of that year:
In addition to all of these variations in its route, another interesting thing about US 240 is that, for a brief period, it was signposted with colored shields in DC (this photo was taken at the Lincoln Memorial, when US 240's terminus was there):
c. 1957, Lindsay (linked to source)
Research and/or image credits: Robert Brooks; Jim Lindsay; Robert Mortell; Alex Nitzman; Mike Roberson; Dale Sanderson; Michael Summa
Page originally created 2005;last updated Sep. 1, 2025.
Page updated
Google Sites
Report abuse