This question is an exact duplicate of:
- from where vs from which [duplicate] 1 answer
I have asked this question before but I would like to ask it again since I have got some new ideas about it.
I think that when referring to a location, the choice between from which and from where actually depends on the things that you want to emphasize.
You have to go to King's Cross Station, from which you can get to every other place in this country by train. (Here, from which is used instead of from where because we focus on the function of the train station. Its location is not particularly important because people are able to travel to other places easily due to its rail service.)
We walked to King's Cross Station, from where we went to our hotel by taxi. (Here from where is used because King's Cross Station's location is important instead of its function as a station)
Then, things get even trickier in the following sentences, but let me explain my idea here.
Currently, America's biggest business partner is China, from which the USA imported more than 2 million tons of goods annually. (Here if we use from which to highlight China's status as a "business partner", it means that the USA imported lots of goods from Chinese local companies.)
Currently, America's biggest business partner is China, from where the USA imported more than 2 million tons of goods annually. (Here, when from where is used, it means that lots of goods are imported from where China is, but it can also be argued that some foreign companies that have branches in China are involved, not just native Chinese companies in China)
Then, I would like to provide some other example to make my idea clearer
- We visited China last year, from where my parents immigrated to the USA fifty years ago. (China as a location)
Sometimes, the position of the word before "from" matters. For example:
Detroit was once the poorest city in the country, from which thousands of people moved to nearby cities to seek jobs every month. (from which=from the city. People do not want to live "inside that city" anymore. They are not just taking daily trips from that location to another location. They are moving out. The function of Detroit as a city is emphasized here.)
The poorest city in the country was Detroit, from where thousands of people moved to nearby cities to seek jobs every month. (from where is used to refer to "and from there". As Detroit is put right in front of "from", and it's a proper name that refers to a location (as well as a city, but not particularly important as the word "city" is put in an earlier position in the sentence), from where is preferred here.
Have I distinguished between from which and from where correctly?