Up to then, until then, up till then
1. Up to then they had only covered half the distance.
2. Until then they had only covered half the distance.
3. Up till then they had only covered half the distance.

Are the three sentences identical and do they mean the same thing? Thank you.

Question

Up to then, until then, up till then
1. Up to then they had only covered half the distance.
2. Until then they had only covered half the distance.
3. Up till then they had only covered half the distance.

Are the three sentences identical and do they  mean the same thing? Thank you.

Answer

They do have the same meaning. A fourth variation is 'Up until then..'.