According the AA Route Planner (GB Edition) the distance is 267.7 miles, this will take about 6 hours and 7 minutes to drive, assuming you take the direct route to the centre of each location and there are no stops, accidents, breakdowns or other hold ups en route.
Holyhead to Edinburgh is 319 miles.
Holyhead to Rhoscolyn = 5.1 miles.
356 miles
147 miles
The distance between Holyhead UK and Swansea UK is about 170 road miles.
82 miles taking A55.
The driving distance is about 231 road miles.
doncaster to holyhead 168.5miles
Holyhead, Isle Of Anglesey to Liverpool, Merseyside = 94 miles.
The driving distance from Holyhead to London is 288 road miles.
About 288 miles on the M1, M6 and A55
Holyhead, Isle Of Anglesey to Gosport, Hampshire = 331.1 miles.