A vote that could redraw the world map

Scotland's voters make their choice in independence referendum

By Laura Smith-Spark and Nic Robertson, CNN

September 18, 2014 -- Updated 

Glasgow, Scotland (CNN) -- Scotland's voters are heading to the polls Thursday to cast their ballots in a landmark referendum on independence from the United Kingdom.

There, they will face a straightforward yes/no question: Should Scotland be an independent country?

More than 4.2 million people have registered to vote, the largest electorate ever in Scotland, and turnout in the referendum is expected to be high.

A vote for independence would mean Scotland, with its population of about 5.3 million, splits from the rest of the United Kingdom, made up of England, Wales and Northern Ireland.

Voting can take place from 7 a.m. until 10 p.m. local time (2 a.m. to 5 p.m. ET) at more than 5,500 polling stations across 32 districts nationwide, from the remote highlands and islands to the big cities of Edinburgh and Glasgow.

What you need to know

Photos: Scotland votes

Voting was brisk at one polling station in Glasgow as the polls opened, with many people voting on the way to work or before taking their children to school.

Results from the different areas will come in overnight into Friday morning local time, with Chief Counting Officer Mary Pitcaithly expected to announce the outcome "around breakfast time."

Bad weather or the sheer volume of votes cast could slow down the counting process. However, the weather forecast appears good so far -- important when some ballot boxes must be collected by helicopter, plane or boat from polling stations on distant islands.

A simple majority is needed for either side to claim victory.

Scotland's First Minister Alex Salmond, who has led the pro-independence "Yes Scotland" campaign, cast his ballot Friday morning in the village of Strichen, Aberdeenshire.

Labour lawmaker Alistair Darling, who has headed the pro-union "Better Together" campaign -- backed by the main parties in Westminster -- voted in Edinburgh, while former Prime Minister Gordon Brown, another pro-union campaigner, voted in the town of Kirkcaldy.

For the first time, the vote has been extended to 16- and 17-year-olds living in Scotland. Nearly 110,000 people younger than 18 have registered to vote.

Voters in the referendum do not have to be British citizens; Commonwealth, Irish and EU citizens who live in Scotland and are registered to vote there can cast a ballot. However, Scots living outside Scotland do not have a say.

Nearly 790,000 people applied for a postal vote -- the largest volume of registration for postal votes ever in Scotland.

CNN, like other broadcasters, is following rules that restrict reporting on details of campaigning until after the polls close.