'to get to river' VERSUS 'to get to the river'

[English teacher]

English Grammar Error, Intermediate level

ESL/EFL Test #21 "Modal Verbs", question 10

We walked for miles and miles that day in fact we even managed to get till river before it got dark.

(a) for
(b) managed
(c) till

English Grammar Error, Intermediate level

ESL/EFL Test #21 "Modal Verbs", answer 10

We walked for miles and miles that day in fact we even managed to get to river before it got dark.

Correct entry: to
The error was: (c) till

You have found the error but your entry is incorrect.
We walked for miles and miles that day in fact we even managed to get to the river before it got dark.
_________________________

Its wrong... It should be to the river, not to river

English teacher

[Yankee]

[Dongocan]

whether or not if i use by instead of to!? is it right!/ please post your comment! thx
An