Almost exactly 500 miles.
176 miles taking I-15 SOUTH.
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.
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.
Weston, Idaho is approximately 15 miles away from West Valley, Utah.
About 115 Miles.
No Idaho is North of Utah.
Google Maps estimates the driving time as 7 hours and 17 minutes.
It's under 100 miles to the border.
It is 383 miles according to Google Maps.
It is in Southwest Idaho, about 54 miles on Interstate 84 from the Oregon border (west) and about 231 miles (on the interstate) from the Utah border to the south.
About 295 miles.
It is 571 miles according to Google Maps.