Modern US 331 was not commissioned until 1953.  In the beginning (1926), there was a different US 331; this is how it was described in AASHO's Apr. 1927 route log:
US 331 lasted for only about 10 years, because it was replaced by an extension of US 29 around 1936.  The entire route was shown on this map:
Picture
c. 1935, Gousha
This photo shows the signage on northbound US 29/AL 113 at the intersection with US 31 in Flomaton:
Picture
Nitzman, Aug. 2002 (unchanged as of 2013)
Before US 29 was extended down through this area, that was the north end of US 331.  Here, we are northbound on US 31:
Picture
Nitzman, Aug. 2002
​The north beginning of US 331 was to the right, on what is now US 29/AL 113. 
This shot was looking south on US 31/US 29/AL 113; today US 29 and AL 113 go left here.  But historically that was the north beginning of US 331:
Picture
Karner, May 2013
The south end of US 331 was at the same intersection where US 29 ends today; more info and photos on the Pensacola page.
Research and/or photo credits: Justin Cozart; Adam Froehlig; Martin Karner; Alex Nitzman; Dale Sanderson; Michael Summa
Page originally created 2002;
last updated Dec. 19, 2021.