176 miles taking I-15 SOUTH.
Almost exactly 500 miles.
I believe you are referring to 'Meadow, Utah'. I could not find a town exactly 315 miles south of Idaho Falls, Idaho on I-15, but there is a town that is 316.7 miles south of Idaho Falls, Idaho named 'Meadow, Utah'. This is probably the town that you are referring to. Of course, that may vary according to how the distance is measured.
731 miles
It is 601 miles with an estimated driving time of 10 hours and 18 minutes according to Google Maps.
731 miles
The distance between Ogden UT and The Dalles OR is about 650 road miles.
560 miles taking this route:Take I-15 SOUTH, from Idaho Falls, to I-80 EAST to CHEYENNE via I-84 EAST (EXIT 340 in UTAH).Take I-80 EAST to Laramie.
286.6
It is 339 miles according to Google Maps.
It is 1,392 miles according to Google Maps.
Around 765.
It is 2,508 miles according to Google Maps.