It was recently announced that Oregon Senators Jason Atkinson and Bruce Starr were seeking to amend a pending transportation bill to raise the speed limits on Oregon's highways and interstates to 75 miles per hour for most vehicles. The change is intended to bring Oregon's speed limit in line with speed limits in neighboring states.
There is a bill pending in Texas to raise speed limits on certain roads there to 85 mph, which would be the highest in the nation.
The determination of appropriate speed limits on different roads is a controversial issue. For resources discussing speed limits see here (motorist perspective), here (state government perspective), and here (insurance industry perspective).