Far and a long way both describe something at a great distance:

I can’t see very far without my glasses on.

San Francisco is a long way from New York.

Far is used mostly in negatives and questions:

There’s a Thai restaurant not far from here.

How far is your house from the station?

A long way is used mostly in affirmative statements but we also use it in questions and negatives:

How long did it take you to get here today?

I left home at half past ten this morning.

Six hours. That’s a long time, isn’t it?

Yeah. It’s a long way.

Not: It’s far.

We have to go to Cathy’s place first to pick her up.

Is it a long way from here?

No, it’s not far.

Far is used in affirmative statements with words such as so, too, enough and as. These expressions can refer to time as well as distance:

So far, we have sent four letters to the Council about the litter on the street. (time until now)

Six months is too far ahead. The restaurant only takes bookings for up to two months in advance.

Where we live is far enough away from the city. I don’t want to move any further away.

From here, you can see as far as the ocean.

Far is also used in comparatives to mean ‘much’:

The roads here are far better than in our country.

Food costs far more in the UK.

We can use by far before a superlative adjective to add emphasis:

With more than seven million people, London is by far the biggest city in England – the second city, Birmingham, has just over one million.

We use the phrase has come a long way to mean ‘has improved or developed’:

Our team has come such a long way. We lost our first game 5-0!

We can use the phrase to be a long way off (+ noun or -ing form) to refer to a long time:

The holidays are a long way off.

We’re a long way off retiring yet, Marlene.