last state to build a freeway?

[agentsteel53]

I was informed today that Louisiana's first segment of freeway opened in 1957, which makes it pretty late in the game. 

my educated guess is that Alaska was the last - 1960s or so.  which was the last in the lower 48?

(IIRC, Hawaii had a section of freeway which would later become H-1 open by 1953.)

[oscar]

My wild guess is that last in the lower 48 would be Arizona, which was generally slow to get on the stick with Interstate construction and other big Federal programs.  But a 1961 AAA southwestern states map says there was one stretch of freeway open in Phoenix by then.

I also have a 1959 road atlas (the "49-state" atlas, coming out in the brief interval between Alaska's and Hawaii's statehoods).  But it's hard to tell from how it marked the highways, and the small scale, whether Arizona or some other western states had any freeways by then.

[NE2]

Alaska is certainly the only one without a freeway in the 1965 RMcN. Can't help beyond that.