Gé hé qiān lǐ yuǎn.

隔河千里遠。

Lit [Although] separated only by a river, [it's as though they were a] thousand leagues apart.

Fig It's hard to know the situation in a different place, (even though it may not be that far away).

Note [See also géshān rú gé tiān below.]

Topics DIFFERENCES KNOWING PLACE SEPARATION