Lying in state means that her coffin has been put in Westminster Hall, protected by guards, so that the public can go in and look at it.
At 2pm on Friday the queue was two-and-a-half miles long and police said that it would take about six hours to get to the front.
On Friday morning the streets of London were filled with people watching the funeral procession.
People camped out
At 11.30 the coffin was carried on a gun carriage from St James's Palace to Westminster Hall.
People camped out on the streets overnight to make sure they got a good view of the proceedings.
Fourteen members of the royal family walked behind the coffin including the Queen Mother's great grandsons Prince William and Harry.
The coffin was draped in the Queen Mother's special flag and her crown was placed on top.
It was the largest procession of its kind on Britain's streets since famous wartime Prime Minister Sir Winston Churchill's funeral in 1965.
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